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iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 1/18 FEATURES o Quadruple hall sensor array for error-tolerant adjustment o Non-sensitive to magnetic stray fields due to differential measurement technique o Interpolator with a resolution of up to 256 angle steps per cycle o Rotational speeds up to 60.000 rpm o 4 buffered I/O stages for signal outputs o Three configuration inputs for operating mode selection o Analog operation modes: - sine/cosine signals controlled to 2 Vpp - triange or sawtooth signal with selectable amplitude o Digital operation modes: - A/B quadrature signals with Z index pulse - Counter pulses for external binary counters o Cascading of multiple iC-MA possible for chain operation o Error signal output for detection of low magnetic field strength o Additional operating modes with reduced power consumption o Standby modus when not enabled o DFN10 package and bare die for flip chip mounting available o Extended temperature range of -40...+125 C APPLICATIONS o o o o o o Analog and digital angle sensors Incremental angular encoders Magnetic multiturn encoders Potentiometer replacement Contactless rotary switch Commutation of brushless DC motors o Flow meter
PACKAGES
DFN10 4 x 4 mm
Chip 2.74 x 1.94 mm
BLOCK DIAGRAM
VDD
VDD
CFG1
SIN
SIN I/O DIG 8 BIT AMP I/O
A
VDD COS
CFG2
HALL SENSOR
GAIN VDD
B
CFG3
SIN +COS GAIN CONTROL
2
2
iC-MA
REFH VPHI
C
I/O
D NEN
VDD
I/O
VREF
MODE SELECT
BIAS
AMPLITUDE ERROR CONTROL
GND
DIG/R
REFL
INTERFACE
Copyright (c) 2009 iC-Haus
http://www.ichaus.com
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 2/18 DESCRIPTION The CMOS device iC-MA consists of a quadruple hall sensor array which has been optimized for the magnetic measurement of angles of rotation. This array permits error-tolerant adjustment of the magnet, reducing assembly efforts. The integrated signal conditioning unit provides a differential sine/cosine signal at the output. The sensor generates one sine cycle per each full rotation of the magnet, enabling the angle to be clearly determined. At the same time the internal amplitude control unit produces an regulated output amplitude of 2Vpp regardless of variations in the magnetic field strength, supply voltage and temperature. Furthermore, signals are provided which enable the sensor amplitude to be assessed and also report any magnet loss. With the aid of the integrated 8-bit sine/digital converter the angle of rotation is determined from the sine/cosine signals. This is output via an incremental interface in a number of selectable resolutions. The zero angle is indicated by an index pulse. The maximum resolution of 8-bit is maintained up to rotations of 60,000 rpm. The absolute angle of rotation can be converted back to a linear analog output signal using the internal D/A converter; here, output voltage limits can be set as required using the external pins. Either a periodic linear signal (sawtooth) or a delta voltage (triangle) can be provided. iC-MA can be easily cascaded in three different modes of chain operation so that several axes of rotation can be scanned. The angle positions of the individual axes can then be read via a common bus. Used in conjunction with a permanent magnet iCMA can act as an encoder system with an integrated magnetic scanning feature. No further components are required.
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 3/18 PACKAGES DFN10 according to the JEDEC standard PIN CONFIGURATION - DFN10 4 mm x 4 mm PIN FUNCTIONS No. Name Function 1 2 3 4 5 6 7 8 9 10 NEN GND CFG2 B A D C CFG3 VDD CFG1 Enable Input, low active Ground Configuration Input 2 Bidirectional Input/Output B Bidirectional Input/Output A Bidirectional Input/Output D Bidirectional Input/Output C Configuration Input 3 +5 V Supply Voltage Configuration Input 1
1 2 3
10 9
4 5
iC-MA ... ...yyww
8
7 6
The Thermal Pad on the bottom of the package should be connected to Ground (GND) on the PCB. Orientation of package label ( MA CODE ...) may vary.
PIN CONFIGURATION - Die 2.74 mm x 1.94 mm
PIN FUNCTIONS No. Name Function 1 2 3 4 5 6 7 8 9 10 NEN GND CFG2 B A D C CFG3 VDD CFG1 Enable Input, low active Ground Configuration Input 2 Bidirectional Input/Output B Bidirectional Input/Output A Bidirectional Input/Output D Bidirectional Input/Output C Configuration Input 3 +5 V Supply Voltage Configuration Input 1
9 10
8
7 6
1
5
2
3
4
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 4/18 ABSOLUTE MAXIMUM RATINGS
Beyond these values damage may occur; device operation is not guaranteed. Item No. Symbol Parameter Supply voltage Voltages at A, B, C, D, NEN, CFG1, CFG2 Current at VDD Current at A, B, C, D, NEN, CFG1, CFG2 Pulse current (Latch-up immunity) ESD-Voltage at all pins Storage temperature Pulse width < 10 s HBM 100 pF discharged over 1.5 k -40 V() < VDD + 0.3 V Conditions Min. -0.3 -0.3 -30 -30 -10 -100 Max. 6 6 30 30 10 100 2 150 V V mA mA mA mA kV C Unit
G001 VDD G002 V() G003 Imx(VDD) G005 Imx() G006 Ilu() G007 Vd() G008 Ts
G004 Imx(GND) Current at GND
THERMAL DATA
Operating conditions: VDD = 5 V 10 % Item No. T01 T02 Symbol Ta Rthja Parameter Ambient temperature Thermal resistance chip/ambient DFN10 on multi-layer test board acc. JEDEC standard Conditions Min. -40 Typ. Max. 125 200 C K/W Unit
All voltages are referenced to ground unless otherwise stated. All currents into the device pins are positive; all currents out of the device pins are negative.
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 5/18 ELECTRICAL CHARACTERISTICS
Operating conditions: VDD = 5 V 10 % , Tj = -40 ... 125 C, unless otherwise noted Item No. 001 002 003 004 005 101 102 103 104 105 106 Symbol Parameter Conditions Min. VDD I(VDD) I(VDD)sb Supply voltage Supply current Standby supply current open pins, normal operation open pins, power reduction mode (PRM) NEN = VDD VDD > 4 V, see figure 6 VDD < 2.6 V 20 10 10 50 2 -0.2 -3 400 -3 3 0.2 3 100 4.5 Typ. 5 14 7 Max. 5.5 21 14 200 V mA mA A s s kA/m mm mm DEG m DEG Unit
General
td(VDD)on Turn on delay td(VDD)off Turn off delay Hext dsens xdis dis hsens Aabs
Hall sensor array Requiered external magnetic field at chip surface strength Diameter of Hall sensor array Displacement of Hall sensor array to package see figure 1 DFN10 package, see figure 1
Angular displacement of chip with DFN10 package reference to package Distance chip surface to top of package Absolute angular position DFN10 package Using magnet with 4 mm diameter, centered to chip, Hext = 20...100 kA/m on output, with external magnetic field amplitude of 20 kA/m
Signal conditioning 201 202 203 204 205 206 207 208 301 302 303 304 401 402 403 404 501 502 503 504 601 602 603 604 605 Voff TC(Voff) Vdc Ratio fhc t()settle V()gain V()ampl AArel f(OSC) TC(OSC) hys Vt()hi Vt()lo V0() Ri() Vt()hi Vt()lo Vt()hys Ipu() Vs()hi Vs()lo tr() tf() Ilk() Offset voltage Temperatur coefficient of offset voltage Output mean value Amplitude ratio of SIN / COS Cut off frequency Settling time Gain output voltage Sine/Cosine amplitude Relative angular error Oscillator frequency Temperature coefficient of oscillator frequency Converter hysteresis Threshold voltage high Threshold voltage low Open circuit voltage Input resistance Threshold voltage high Threshold voltage low Hysteresis Pull-up current Saturation voltage high Saturation voltage low Rise time Fall time Leackage current Vt()hys = Vt()hi - Vt()lo V() = 0...VDD - 1 V Vs()hi = VDD - V(), I() = -4 mA I() = 4 mA CL() = 50 pF CL() = 50 pF NEN = high, V() = 0 ... VDD -5 0.8 100 -240 -120 250 -25 0.4 0.4 60 60 5 60 25 43 45 150 V()ampl = V()max - Vdc with reference to one periode, see fig. 2 to 70 % amplitude, Hext = 40 kA/m 0.05 0.9 -20 200 256 -0.1 1 78 40 57 750 2 1.0 -50 -50 45 0.95 50 1.00 20 80 150 4.0 1.1 20 300 50 50 55 1.05 kHz s V V % kHz %/K LSB % VDD % VDD % VDD k V V mV A V V ns ns A mV V/K %VDD
Sine-to-digital converter
Configuration inputs CFG1, CFG2, CFG3
Enable input NEN
Digital outputs: A, B, C, D
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 6/18 ELECTRICAL CHARACTERISTICS
Operating conditions: VDD = 5 V 10 % , Tj = -40 ... 125 C, unless otherwise noted Item No. 606 607 701 702 703 704 801 802 803 804 805 Symbol Vc()hi Vc()lo Vt()hi Vt()lo Vt()hys Ipd() SR fhc() I() R()eda R()ada Parameter Clamp voltage high Clamp voltage low Threshold voltage high Threshold voltage low Hysterese Pull-down current Slew Rate Cut off frequency Output current Input resistance DA-converter Output resistance DA-converter between pin B and pin C at pin A Vt()hys = Vt()hi - Vt()lo V() = 1 V...VDD 0.8 300 5 2 500 -1 6 8 100 1 10 30 65 Conditions Min. Vc()hi = V() - VDD, NEN = high, I() = 4 mA NEN = high, I() = -4 mA 0.3 -1.5 Typ. Max. 1.6 -0.3 2 V V V V mV A V/s kHz mA k k Unit
Digital inputs: A, B, C, D
Analog outputs: A, B, C, D
hsens
0% 50%
dsens
twhi()/T
AArel
0% 100% AArel
Figure 1: Location of die in DFN10 package
Figure 2: Definition of relative angular error
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 7/18 OPERATING CONDITIONS: Logic
Operating conditions: VDD = 5 V 10 %, Tj = -40...125 C, unless otherwise noted Input level low = 0...0.45 V, high = 2.4 V...VDD, timing according Fig. 3 Item No. Logic I001 ts(NEN) I002 tp(NEN) I003 tp(SIG1) I004 tp(SIG2) I005 tp(CFGx) Setup time NEN Delay time NENO Delay time SIG1 Delay time SIG2 Setup time at CFGx, x = 1..3 CLK : low high (see figure 12) CLK : high low (see figure 12) CL() = 50 pF (see figure 12) CL() = 50 pF (see figure 12) see figure 6 30 30 60 2 10 ns ns s s s Symbol Parameter Conditions Min. Max. Unit
V Input/Output
2.4V 2.0V 0.8V 0.45V
t 1 0
Figure 3: Reference levels for delays
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 8/18 The sensor principle cal, diametrically magnetized permanent magnet (with a diameter D of 4 mm and length L of 4 mm, for example) provides optimal sensor signals. Magnetic materials such as neodymium iron boron (NdFeB) or samarium cobalt (SmCo) are very well suited to the sensor and not readily influenced by external magnetic disturbance fields. The L/D ratio of a magnet magnetized to saturation point has a bearing on the resulting field strength and should lie within the region of 0.3 to 2. iC-MA has four Hall sensors which are used to determine angles and to convert the magnetic field into a measurable Hall voltage. Only the z component of the magnetic field is assessed where the line of magnetic flux must pass through two facing Hall sensors in the opposite direction. An example line of magnetic flux is given in Figure 4. The Hall sensors have been arranged in such a way that the assembly of the magnet with iC-MA is extremely tolerant. Two Hall sensors combined generate a differential Hall signal. If the magnet is rotated along its longitudinal axis sine and cosine output voltages are created which can be used to determine angles.
N
S
z
y x
B
+Bz
-Bz
Figure 4: The principle of magnetic field measurement using a Hall sensor In conjunction with a permanent magnet iC-MA can be used to create a complete encoder system. A cylindri-
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 9/18 Definition of the angle of rotation and the direction of rotation The arrangement of permanent magnet and iC-MA illustrated in Figure 5, where the diametrically magnetized magnet is placed vertical to the chip's surface, is used to determine both the angle and direction of rotation. An angle of 0 lies along the diagonal. Rotating the magnet clockwise as shown in Figure 5 increases the angular position and hence the output signal.
N
S
N
S
0
Figure 5: Definition of the angle and direction of rotation
Programming the configuration iC-MA has 28 modes of operation (see tables on the following pages). After the device has been switched on or "woken up" from standby mode by a low signal at pin NEN the levels at the configuration inputs CFG1 to CFG3 are assessed. These three-level inputs can be connected to GND (low), left open (open) or connected to VDD (high). For correct identification, a setup time of at least tp(CFGx) = 4 s must be maintained between programming the configuration and activating the device. While the device is active changes in signal at the configuration inputs are ignored. If several iC-MAs are connected in series in chain operation (see the description of functions on page 13) it must be ensured that the NEN input of the devices is switched to low during the various clock cycles and that the programming default does thus not lie within the active phase of the devices. In standby all ports are switched to tristate, i.e. high impedance. Only in chain operation modes port D is active high so that the devices arranged further behind can also be deactivated.
4V VDD
NEN
iC-MA active CFGx
iC-MA active
td(VDD)on tp(CFGx) tp(CFGx)
Figure 6: Programming the configuration
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 10/18 Operating modes
Mode NEN CFG1 CFG2 Analog low low S-Sensor low D-Sensor low open low D-Sensor low high low Linear output R-Sensor low low open low open open low high open low high open Chain-Mode low high AB-Chain low D-Chain low open high S-Chain low high high Incr. ABZ ABZ 8-1 low low low ABZ 8-0 low open low ABZ 7-1 low low open ABZ 7-0 low open open ABZ 6-1 low low high ABZ 6-0 low open high ABZ 8-1 low low low ABZ 8-0 low open low ABZ 7-1 low low open ABZ 7-0 low open open ABZ 6-1 low low high ABZ 6-0 low open high Incr. CLK CLK 8 low high low CLK 6 low high high DIR 8 low high low DIR 6 low high high Test (for iC-Haus use only) low high open Test Standby high x x
1
CFG3 low low low low low low high low low low open open open open open open high high high high high high open open high high open x
Port A PSIN PSIN PSIN VTRI VTRI VSAW VSAW A PSIN/NSIN PSIN/VREF A A A A A A A A A A A A NCLKUP NCLKUP NCLK NCLK
Port B VREF NSIN NSIN REFH REFH REFH REFH CLK CLK CLK B B B B B B B B B B B B NCLKDN NCLKDN DIR DIR
Port C PCOS PCOS PCOS MSB MSB REFL REFL B PCOS/NCOS PCOS/GAIN Z Z Z Z Z Z Z Z Z Z Z Z NCLR NCLR NCLR NCLR
Port D GAIN NCOS NCOS NERR GAIN NERR GAIN NENO NENO NENO NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR
Res. Comments
PRM
8 8 8 8 8
8 8 7 7 6 6 8 8 7 7 6 6 8 6 8 6
AB=1 AB=0 AB=1 AB=0 AB=1 AB=0 AB=1, PRM AB=0, PRM AB=1, PRM AB=0, PRM AB=1, PRM AB=0, PRM
Test TRI TRI TRI TRI1
In chain operation port D is active high so that the backend devices can also be deactivated.
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 11/18 Analog modes of operation
Mode Analog S-Sensor D-Sensor D-Sensor
NEN CFG1 CFG2 CFG3 low low low low open high low low low low low low
Port A PSIN PSIN PSIN
Port B VREF NSIN NSIN
Port C PCOS PCOS PCOS
Port D GAIN NCOS NCOS
Res. Comment
PRM
In the analog modes of operation the amplified Hall voltages are available at the output ports. The sine/ cosine output signals are controlled to have stable amplitudes of 1 V and referenced to a DC value equivalent to half of the supply voltage (VREF). Due to the internal signal conditioning unit, no special adjustment is required. An externally connected interpolator can be used if further trimming of the output signals is desired.
5
Signal GAIN allows conclusions to be drawn as to the operating point of the sensor. This is influenced by the amplitude of the magnetic field, the sensor supply voltage and temperature. The higher the GAIN potential, the greater the necessary amplification of the Hall voltages; the external magnetic field is smaller. Besides recording the direction of magnetization of the permanent magnet the distance between the magnet and sensor may also be assessed using the GAIN signal. If the gain is insufficient to boost the Hall voltages to 2 Vss the amplitude control reaches its upper limit and the output amplitude becomes smaller. The GAIN signal can be used to adjust the permanent magnet. If the central point of both the magnet and sensor iC-MA are the same the GAIN signal has no harmonics. A misaligned sensor must readjust the operating point depending on the angle; the GAIN signal varies in amplitude. To adjust the sensor to the magnet this must be shifted along its X- and Y-axis so that the GAIN signal has to readjust as little as possible. D sensor mode In D sensor mode differential sine (pin A and pin B) and cosine (pin C and pin D) signals are supplied at the output; as opposed to S sensor mode inverted Hall signals are now also available at the ports. The advantage of this mode of operation is the doubled signal amplitude of the differential Hall voltages and the lack of dependence on reference voltage VREF. The angle is now calculated via the ratio of the difference between PSIN and NSIN and between PCOS and NCOS. D sensor mode is also available with a reduced power consumption (PRM or Power Reduced Mode). In this mode the Hall sensor is supplied with current less frequently, reducing the power consumption. Here it must be observed that the maximum rotating frequency also drops by a factor of 2.
4
PSIN NCOS
Voltage [V]
3
VREF
2
NSIN PCOS
1
GAIN
0 0 100 200 300 400 500 600 700
Time [s]
Figure 7: Analog mode output signals after switching on the device S sensor mode After the device has been activated via NEN = low the sensor is set to its operating point. All signals are referenced to half the supply voltage (VREF). In S sensor mode this potential is available at port B. Ports A and C output the sine and cosine Hall voltages set to 2 Vss. The angle can be calculated from the relation of the sine voltage (difference in voltage PSIN to VREF) to the cosine voltage (difference in voltage PCOS to VREF). The device supplies an angle which remains non-ambiguous over a 360 rotation of the permanent magnet.
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 12/18 Resistor modes of operation
Mode NEN CFG1 CFG2 CFG3 Linear output low open low R-Sensor low low open open low low high open low low high open high
Port A VTRI VTRI VSAW VSAW
Port B REFH REFH REFH REFH
5
Port C MSB MSB REFL REFL
Port D NERR GAIN NERR GAIN
Res. Comments 8 8 8 8
Voltage [V]
Resistor modes of operation In R sensor mode the taps of an integrated resistive divider are selected depending on the angular position ("potentiometer replacement"). The value of the absolut angular position acts as a "wiper" and selects one of the 256 taps on the resistor chain.
4
REFH
3
VSAW
2
1
REFL
0 0 45 90 135 180 225 270 315 360 405 450
Angle []
Figure 8: Potentiometer equivalents for resistor mode operations In modes with a sawtooth voltage VSAW at port A the angle is converted into a linear voltage which lies within thresholds REFH and REFL at ports B and C (see Figure 9). The integrated resistor chain is directly available at the ports so that thresholds REFH and REFL can also be reversed. Depending on the selected mode either a GAIN signal or a NERR error signal are present at port D to monitor the amplitude. If the amplitude is at least 70 %, NERR is high; should the amplitude sink to below 50 % of the set amplitude, NERR switches to active low. Modes of operation with a triangular voltage VTRI avoids the discontinuity at the zero angular position. Signal MSB can be used to differentiate between the first and second half rotation. The delta voltage is limited by thresholds REFH and GND. As in VSAW mode both GAIN and NERR signals are available.
Figure 9: R-Sensor mode with sawtooth output voltage VSAW
5
4
REFH
Voltage [V]
3
2
VTRI
1
MSB
0 0
45
90
135
180
225
270
315
360
405
450
Angle []
Figure 10: R-Sensor mode with triangular output voltage VTRI
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 13/18 AB chain, D chain and S chain modes
Mode NEN Chain operation AB chain low D chain low S chain low
CFG1 CFG2 CFG3 low open high high high high low low low
Port A A PSIN/NSIN PSIN/VREF
Port B CLK CLK CLK
Port C B PCOS/NCOS PCOS/GAIN
Port D NENO NENO NENO
Res. Comments 8
CLK MA 0 CLK NEN(0) NEN NENO
iC-MA
MA 1 CLK NEN(1) NEN NENO
iC-MA
MA 2 CLK NEN(2) NEN NENO
iC-MA
NEN(3)
A C
A C
A C
A C
Figure 11: Chain modes for iC-MA
CLK
ts(NEN)
NEN(0)
tp(NEN0)
NEN(1)
NEN(2)
tp(SIG1) tp(SIG2)
NEN(3)
ts(NEN)
TRISTATE
TRISTATE
TRISTATE
TRISTATE
TRISTATE
TRISTATE
TRISTATE
A
PSIN0
NSIN0
PSIN1
NSIN1
PSIN2
NSIN2
B
PCOS0
NCOS0
PCOS1
NCOS1
PCOS2
NCOS2
MA 0 active
MA 1 active
MA 2 active
Figure 12: Signal patterns in D chain mode
TRISTATE
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 14/18 In the various chain modes multiple iC-MAs can be arranged in a chain (see Figure 11) where all of the devices are connected by a shared CLK line (pin B). The NEN input is evaluated synchronously with the rising CLK edge. If the NEN input is switched to low, the device is active during the following CLK cycle(s). To allow the devices to be cascaded a delayed enable signal is generated at output pin NENO (pin D) with which the follow-on device can be activated. If the NEN input of the first device in the chain is reset to high, all devices in the chain are deactivated. Bus lines A (pin A) and C (pin C) are activated by tristate output stages which are high impedance when NEN is high and CLK is low and also following the second rising CLK edge. AB chain mode In AB chain mode two A/B digital incremental signals are generated at ports A and C. The two square-wave signals are phase shifted at either +90 or -90, depending on the direction of rotation. Following a CLK pulse the next device in the chain is enabled. Here the falling CLK edge deactivates the current device (e.g. MA 1 in Figure 11) and activates the next device in the chain (MA 2) with a low signal at its NEN input. After a device has been activated the two bus lines A (port A) and B (port C) are first switched to low (see Figure 12). This is then followed by the incremental signals being output, starting at the zero position. In the event of error the bus lines remain low. D chain mode In D chain mode differential sine and cosine signals are generated at ports A and C. During the first clock pulse signals PSIN and PCOS are presented to the bus; during the second pulse signals NSIN and NCOS are on the bus (see Figure 12). In this mode each device is thus active for two clock pulses. During the first clock pulse the non-inverted sine (port A) and cosine (port C) signals are first presented to the bus, with the inverted signals following on the positive CLK edge during the second pulse. The falling CLK edge in the second clock pulse deactivates the current device and activates the following device in the chain with a low signal at its NEN input. S chain mode In S chain mode the non-inverted sine (port A) and cosine (port C) signals are presented to the bus during the first clock pulse, with the mean of the two signals (VREF, port A) and the amplification signal GAIN (port C) following on the positive CLK edge of the next pulse. Each device is thus active for two clock pulses. The falling CLK edge in the second clock pulse deactivates the current device and activates the following device in the chain with a low signal at its NEN input. The sine and cosine signals can be assessed using signal VREF. Signal GAIN (pin D) indicates iC-MA's internal amplification (see Electrical Characteristics No. 207) and can be used to estimate the signal amplitude of the internal Hall sensor. The GAIN signal can also be used to adjust the rotary axis of the magnet to the center of the chip.
NEN CLK NENO 5
Voltage [V]
4 3 2 1 0 0 100 200
A
C
300
400
500
600
700
Time [s]
Figure 13: Bus signals and control signals in S chain mode
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 15/18 Incremental ABZ modes
Mode NEN Incr. ABZ ABZ 8-1 low ABZ 8-0 low ABZ 7-1 low ABZ 7-0 low ABZ 6-1 low ABZ 6-0 low ABZ 8-1 low ABZ 8-0 low ABZ 7-1 low ABZ 7-0 low ABZ 6-1 low ABZ 6-0 low
CFG1 CFG2 CFG3 low open low open low open low open low open low open low low open open high high low low open open high high open open open open open open high high high high high high
Port A A A A A A A A A A A A A
Port B B B B B B B B B B B B B
Port C Z Z Z Z Z Z Z Z Z Z Z Z
Port D NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR
Res. Comments 8 8 7 7 6 6 8 8 7 7 6 6 AB=1 AB=0 AB=1 AB=0 AB=1 AB=0 AB=1, PRM AB=0, PRM AB=1, PRM AB=0, PRM AB=1, PRM AB=0, PRM
iC-MA has an 8-bit sine/digital converter which can convert the sine/cosine sensor signals into a digitized angle. This angle is made available at the ports as an incremental value. Signal Z is always high when the angle is 0; otherwise the signal is low. In all incremental modes of operation error signal NERR is available so that the plausibility of the counter value can be verified. At an amplitude which is less than 50 % of the set amplitude the error signal switches to low; at an amplitude greater than 70 % the error signal is reset, i.e. set to high. Three different quantities regarding the number of edges per rotation of the magnet can be selected. These are a resolution of 6 bits (64 edges per rotation), 7 bits (128 edges) or 8 bits (256 edges). The conversion process is count-safe, i. e. the output of all edges up to the current angle position is guaranteed as long as the input frequency is less than the maximum possible rotation. All incremental resolutions also have a reduced power consumption mode(PRM). In this mode the Hall sensor is supplied with current intermittently, reducing the power consumption. Here it must be noted that the maximum input frequency drops by a factor of 2. A distinction can be made between the various modes of operation by studying the level of the AB signals on the Z pulse. In mode AB = 1 signals A and B are both high, as is Z at an angle of 0. In mode AB = 0, however, both signals A and B are low when the Z signal is high. Firstly, the behavior of the sensor on switching on the device is described when the permanent magnet rotates in the direction of the increasing angle (Figure
14). After switching on the sensor via NEN at low the sensor looks for its operating point. If 70 % of the set amplitude is achieved the error signal is reset. An error status during this phase is also signaled when signals A and B are high and Z low. In an error-free state Z is always high when the angle is 0. iC-MA continues to search for its operating point by outputting the angle of the external magnetic field at maximum count frequency via the incremental interface. Once the angle has been obtained the device follows a changed input signal in real time. The edge frequency is thus 256 times the frequency of rotation of the magnet at a set resolution of 8 bits. If a (rising) edge reaches B before a (rising) edge A, this means that the counter value has risen. If the edge reaches A before B, however, this indicates that the absolute value is lower.
NEN
NERR
A
B
Z
Time [us]
Figure 14: Incremental signals after switching on the device, counting up
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 16/18 as possible. If this absolute angle is between 0 and 180 the device counts up to the operating point; if the angle is between 180 and 360, it first counts down. Starting when the device is switched on all edges are output until the absolute position is reached. The setup has to wait until a certain time has elapsed; this is dependent on the selected resolution and is the settling time of the sensor until the error bit is deleted plus the time needed to count up or down to the absolute position. With a resolution of 8 bits and an angle of 180, for example, this period constitutes 100 s sensor settling time plus 128 times 4 s until the absolute position has been pinpointed. The absolute position is thus available after a maximum of 612 s has elapsed.
Time [us]
NEN
NERR
A
B
Z
Figure 15: Incremental signals after switching on the device, counting down Always starting at an angle of 0 the device begins searching for the absolute angle, locating it as quickly
By way of example Figure 15 illustrates how the incremental interface behaves when the device first counts down to the absolute position and the magnet then rotates forwards, with the sensor following with the relevant sequence. The Z signal is synchronous with A and B at low.
Incremental CLK modes
Mode NEN CFG1 CFG2 Inkr. CLK CLK 8 low high low CLK 6 low high high DIR 8 low high low DIR 6 low high high
CFG3 open open high high
Port A NCLKUP NCLKUP NCLK NCLK
Port B NCLKDN NCLKDN DIR DIR
Port C NCLR NCLR NCLR NCLR
Port D NERR NERR NERR NERR
Res. Comments 8 6 8 6
CLK-INC mode In CLK-INC mode two different count signals are provided for the countup and countdown sequences. Depending on the direction of rotation either signal NCLKUP (pin A) is pulsed when the device counts up or signal NCLKDN (pin B) when the device counts down. In each case the remaining signal is high. The zero angle is displayed by the NCLR index track which can serve as an asynchronous reset for an external counter. Figure 16 demonstrates how iC-MA behaves in CLKINC mode, firstly when it counts up from the zero position and then, following a change in the direction of rotation, when it counts back down to an angle of 0. This mode permits the operation of external binary counter modules (such as 74HC/HCT193, for example), with signal NCLR (pin C) being used to reset the counter. With a rising edge of clock signal NCLKUP and a high at NCLKDN the counter status is incremented; with a rising edge of clock signal NCLKDN
and a high at NCLKUP the counter status is decremented. Two 4-bit counters can be cascaded here to create a full 8-bit counter.
NCLUP
NCLDN
NCLR
Time [us]
Figure 16: CLK-INC mode
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 17/18
DATA INPUT VDD
P0 CFG1 CFG2 CFG3 NEN NCLUP NCLDN CPU CPD NPL Q0
P1
P2
P3 TCU
P0 CPU CPD NPL Q0
P1
P2
P3 TCU
the value of the DIR signal. A low at DIR triggers a countup; a high causes the setup to count down. Figure 17 shows a countup sequence followed by a countdown sequence, both across the zero position.
iC-MA
NCLR NERR RESET GND
74HCT193
Q1 Q2
TCD MR
74HCT193
Q1 Q2
TCD MR
Q3
Q3
CLK
OUTPUT
Figure 17: iC-MA with 74HC/HCT193
binary
counter
DIR
DIR-INC mode In DIR-INC mode a change in angle for both directions of rotation generates an output pulse for signal CLK (pin A). Signal DIR (pin B) gives the direction of rotation. This mode permits the operation of external binary counter modules (such as 74HC/HCT191, for example), with signal NCLR (pin C) being used to reset the external counter. With a rising edge at CLK the counter status is counted up or down, depending on
NCLR
Time [us]
Figure 18: DIR-INC mode
iC-Haus expressly reserves the right to change its products and/or specifications. An Infoletter gives details as to any amendments and additions made to the relevant current specifications on our internet website www.ichaus.de/infoletter; this letter is generated automatically and shall be sent to registered users by email. Copying - even as an excerpt - is only permitted with iC-Haus approval in writing and precise reference to source. iC-Haus does not warrant the accuracy, completeness or timeliness of the specification on this site and does not assume liability for any errors or omissions in the materials. The data specified is intended solely for the purpose of product description. No representations or warranties, either express or implied, of merchantability, fitness for a particular purpose or of any other nature are made hereunder with respect to information/specification or the products to which information refers and no guarantee with respect to compliance to the intended use is given. In particular, this also applies to the stated possible applications or areas of applications of the product. iC-Haus conveys no patent, copyright, mask work right or other trade mark right to this product. iC-Haus assumes no liability for any patent and/or other trade mark rights of a third party resulting from processing or handling of the product and/or any other use of the product. As a general rule our developments, IPs, principle circuitry and range of Integrated Circuits are suitable and specifically designed for appropriate use in technical applications, such as in devices, systems and any kind of technical equipment, in so far as they do not infringe existing patent rights. In principle the range of use is limitless in a technical sense and refers to the products listed in the inventory of goods compiled for the 2008 and following export trade statistics issued annually by the Bureau of Statistics in Wiesbaden, for example, or to any product in the product catalogue published for the 2007 and following exhibitions in Hanover (Hannover-Messe). We understand suitable application of our published designs to be state-of-the-art technology which can no longer be classed as inventive under the stipulations of patent law. Our explicit application notes are to be treated only as mere examples of the many possible and extremely advantageous uses our products can be put to.
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 18/18 ORDERING INFORMATION
Type iC-MA
Package DFN10 4 mm x 4 mm Chip
Order Designation iC-MA DFN10 iC-MA CHIP iC-MA EVAL MA1D
iC-MA evaluation board
For technical support, information about prices and terms of delivery please contact: iC-Haus GmbH Am Kuemmerling 18 D-55294 Bodenheim GERMANY Tel.: +49 (61 35) 92 92-0 Fax: +49 (61 35) 92 92-192 Web: http://www.ichaus.com E-Mail: sales@ichaus.com
Appointed local distributors: http://www.ichaus.com/sales_partners

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