View UC2526Q_242885.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

UC1526 UC2526 UC3526
Regulating Pulse Width Modulator
FEATURES
* * * * * * * * * * * * * * 8 To 35V Operation 5V Reference Trimmed To 1% 1Hz To 400kHz Oscillator Range Dual 100mA Source/Sink Outputs Digital Current Limiting Double Pulse Suppression Programmable Deadtime Under-Voltage Lockout Single Pulse Metering Programmable Soft-Start Wide Current Limit Common Mode Range TTL/CMOS Compatible Logic Ports Symmetry Correction Capability Guaranteed 6 Unit Synchronization
DESCRIPTION
The UC1526 is a high performance monolithic pulse width modulator circuit designed for fixed-frequency switching regulators and other power control applications. Included in an 18-pin dual-in-line package are a temperature compensated voltage reference, sawtooth oscillator, error amplifier, pulse width modulator, pulse metering and setting logic, and two low impedance power drivers. Also included are protective features such as soft-start and under-voltage lockout, digital current limiting, double pulse inhibit, a data latch for single pulse metering, adjustable deadtime, and provision for symmetry correction inputs. For ease of interface, all digital control ports are TTL and B-series CMOS compatible. Active LOW logic design allows wired-OR connections for maximum flexibility. This versatile device can be used to implement single-ended or push-pull switching regulators of either polarity, both transformerless and transformer coupled. The UC1526 is characterized for operation over the full military temperature range of -55C to +125C. The UC2526 is characterized for operation from -25C to +85C, and the UC3526 is characterized for operation from 0 to +70C.
BLOCK DIAGRAM
6/93
UC1526 UC2526 UC3526 ABSOLUTE MAXIMUM RATINGS (Note 1, 2)
Input Voltage (+VIN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +40V Collector Supply Voltage (+VC) . . . . . . . . . . . . . . . . . . . . . +40V Logic Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +5.5V Analog Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +VIN Source/Sink Load Current (each output) . . . . . . . . . . . . . 200mA Reference Load Current . . . . . . . . . . . . . . . . . . . . . . . . . . . 50mA Logic Sink Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15mA Power Dissipation at TA = +25C (Note 2) . . . . . . . . . . 1000mW Power Dissipation at TC = +25C (Note 2) . . . . . . . . . . 3000mW Operating Junction Temperature . . . . . . . . . . . . . . . . . . +150C Storage Temperature Range . . . . . . . . . . . . . . -65C to +150C Lead Temperature (soldering, 10 seconds) . . . . . . . . . . +300C Note 1: Values beyond which damage may occur. Note 2: Consult packaging section of databook for thermal limitations and considerations of package.
RECOMMENDED OPERATING CONDITIONS (Note 3)
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +8V to +35V Collector Supply Voltage . . . . . . . . . . . . . . . . . . . +4.5V to +35V Sink/Source Load Current (each output) . . . . . . . . . 0 to 100mA Reference Load Current . . . . . . . . . . . . . . . . . . . . . . 0 to 20mA Oscillator Frequency Range . . . . . . . . . . . . . . . . 1Hz to 400kHz Oscillator Timing Resistor . . . . . . . . . . . . . . . . . . . 2k to 150k Oscillator Timing Capacitor . . . . . . . . . . . . . . . . . . . 1nF to 20F Available Deadtime Range at 40kHz . . . . . . . . . . . . . 3% to 50% Operating Ambient Temperature Range UC1526 . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55C to +125C UC2526 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -25C to +85C UC3526 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0C to +70C Note 3: Range over which the device is functional and parameter limits are guaranteed.
CONNECTION DIAGRAMS
DIL-18, SOIC-18 (TOP VIEW) J or N Package, DW Package PLCC-20, LCC-20 (TOP VIEW) Q and L Packages
PACKAGE PIN FUNCTION FUNCTION PIN
N/C +Error -Error Comp. CSS _ _____ Reset - Current Sense + Current Sense _________ Shutdown RTIMING CT RD Sync Output A VC N/C Ground Output B +VIN VREF
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
ELECTRICAL CHARACTERISTICS: +VIN = 15V, and over operating ambient temperature, unless otherwise
specified, TA = TJ. PARAMETER Reference Section (Note 4) Output Voltage Line Regulation Load Regulation Temperature Stability Total Output Voltage Range Short Circuit Current Under -Voltage Lockout _______ RESET Output Voltage TJ = + 25C +VIN = 8 to 35V IL = 0 to 20mA Over Operating TJ Over Recommended Operating Conditions VREF = 0V VREF = 3.8V VREF = 4.8V 2.4 4.90 25 4.95 5.00 10 10 15 5.00 50 0.2 4.8 5.05 20 30 50 5.10 100 0.4 2.4 4.85 25 4.90 5.00 10 10 15 5.00 50 0.2 4.8 5.10 30 50 50 5.15 100 0.4 V mV mV mV V mA V V TEST CONDITIONS UC1526 / UC2526 MIN TYP MAX MIN UC3526 TYP MAX UNITS
Note 4: IL = 0mA.
2
UC1526 UC2526 UC3526 ELECTRICAL CHARACTERISTICS: +VIN = 15V, and over operating ambient temperature, unless otherwise
specified, TA = TJ. PARAMETER Oscillator Section (Note 5) Initial Accuracy Voltage Stability Temperature Stability Minimum Frequency Maximum Frequency Sawtooth Peak Voltage Sawtooth Valley Voltage Error Amplifier Section (Note 6) Input Offset Voltage Input Bias Current Input Offset Current DC Open Loop Gain HIGH Output Voltage LOW Output Voltage Common Mode Rejection Supply Voltage Rejection PWM Comparator (Note 5) Minimum Duty Cycle Maximum Duty Cycle HIGH Output Voltage LOW Output Voltage HIGH Input Current LOW Input Current Current LImit Comparator (Note 7) Sense Voltage Input Bias Current Soft-Start Section Error Clamp Voltage Cs Charging Current HIGH Output Voltage LOW Output Voltage Collector Leakage Rise Time Fall Time Power Consumption (Note 9) Standby Current RESET = +0.4V RESET =+2.4V ISOURCE = 20mA ISOURCE = 100mA ISINK = 20mA ISINK = 100mA VC = 40V CL = 1000pF CL = 1000pF ____________ SHUTDOWN = +0.4V 50 12.5 12 0.1 100 13.5 13 0.2 1.2 50 0.3 0.1 18 0.3 2.0 150 0.6 0.2 30 0.4 150 50 12.5 12 0.1 100 13.5 13 0.2 1.2 50 0.3 0.1 18 0.3 2.0 150 0.6 0.2 30 0.4 150 V A V V V V A s s mA RS 50 90 100 -3 110 -10 80 100 -3 120 -10 mV A VCOMPENSATION = +0.4V VCOMPENSATION = +3.6V ISOURCE =40A ISINK = 3.6mA VIH = +2.4V VIL = +0.4V 45 2.4 49 4.0 0.2 -125 -225 0.4 -200 -360 0 45 2.4 49 4.0 0.2 -125 -225 0.4 -200 -360 0 % % V V A A RL 10M VPIN1-VPIN2 150mV, ISOURCE = 100A VPIN2-VPIN1 150mV, ISINK = 100A Rs 12k +VIN = 12 to 18V 70 66 64 3.6 RS 2k 2 -350 35 72 4.2 0.2 94 80 0.4 70 66 5 -1000 100 60 3.6 2 -350 35 72 4.2 0.2 94 80 0.4 10 -2000 200 mV nA nA dB V V dB dB TJ = + 25C +VIN = 8 to 35V Over Operating TJ RT = 150k, CT = 20F RT = 2k, CT = 1.0nF +VIN = 35V +VIN = 8V 0.5 400 3.0 1.0 3.5 0.5 3 0.5 7 8 1 10 1 400 3.0 1.0 3.5 3 0.5 3 8 1 5 1 % % % Hz kHz V V TEST CONDITIONS UC1526 / UC2526 MIN TYP MAX MIN UC3526 TYP MAX UNITS
Digital Ports (SYNC, SHUTDOWN, and RESET)
Output Drivers (Each Output) (Note 8)
Note 4: IL = 0mA. Note 5: FOSC = 40kHz (RT = 4.12k 1%, CT = 0.1F 1%, RD = 0)
Note 6: VCM = 0 to +5.2V Note 8: VC = +15V Note 9: +VIN = +35V, RT = 4.12k
3
UC1526 UC2526 UC3526 APPLICATIONS INFORMATION
Voltage Reference
The reference regulator of the UC1526 is based on a temperature compensated zener diode. The circuitry is fully active at supply voltages above +8V, and provides up to 20mA of load current to external circuitry at +5.0V. In systems where additional current is required, an external PNP transistor can be used to boost the available current. A rugged low frequency audio-type transistor should be used, and lead lengths between the PWM and transistor should be as short as possible to minimize the risk of oscillations. Even so, some types of transistors may require collector-base capacitance for stability. Up to 1 amp of load current can be obtained with excellent regulation if the device selected maintains high current gain.
Figure 2. Under-Voltage Lockout Schematic
Soft-Start Circuit
Figure 1. Extending Reference Output Current Under-Voltage Lockout The under-voltage lockout circuit protects the UC1526 and the power devices it controls from inadequate supply voltage, If +VIN is too low, the circuit disables the output _______ drivers and holds the RESET pin LOW. This prevents spurious output pulses while the control circuitry is stabilizing, and holds the soft-start timing capacitor in a discharged state. The circuit consists of a +1.2V bandgap reference and comparator circuit which is active when the reference voltage has risen to 3VBE or +1.8V at 25C. When the reference voltage rises to approximately +4.4V, the circuit _______ enables the output drivers and releases the RESET pin, allowing a normal soft-start. The comparator has 200mV of hysteresis to minimize oscillation at the trip point. When +VIN to the PWM is removed and the reference _______ drops to +4.2V, the under-voltage circuit pulls RESET LOW again. The soft-start capacitor is immediately discharged, and the PWM is ready for another soft-start cycle. The UC1526 can operate from a +5V supply by connecting the VREF pin to the +VIN pin and maintaining the supply between +4.8 and +5.2V.
The soft-start circuit protects the power transistors and rectifier diodes from high current surges during power supply turn-on. When supply voltage is first applied to the _______ UC1526, the under-voltage lockout circuit holds RESET LOW with Q3. Q1 is turned on, which holds the soft-start capacitor voltage at zero. The second collector of Q1 clamps the output of the error amplifier to ground, guaranteeing zero duty cycle at the driver outputs. When the _______ supply voltage reaches normal operating range, RESET will go HIGH. Q1 turns off, allowing the internal 100mA current source to charge CS. Q2 clamps the error amplifier output to 1VBE above the voltage on CS. As the softstart voltage ramps up to +5V, the duty cycle of the PWM linearly increases to whatever value the voltage regulation loop requires for an error null.
Figure 3. Soft-Start Circuit Schematic Digital Control Ports The three digital control ports of the UC1526 are bi-directional. Each pin can drive TTL and 5V CMOS logic directly, up to a fan-out of 10 low-power Schottky gates. Each pin can also be directly driven by open-collector
4
APPLICATIONS INFORMATION (cont.)
TTL, open-drain CMOS, and open-collector voltage comparators; fan-in is equivalent to 1 low-power Schottky gate. Each port is normally HIGH; the pin is pulled LOW _____ _ to activate the particular function. Driving SYNC LOW initiates a discharge cycle in the oscillator. Pulling ____________ SHUTDOWN LOW immediately inhibits all PWM output _______ pulses. Holding RESET LOW discharges the soft-start capacitor. The logic threshold is +1.1V at +25C. Noise immunity can be gained at the expense of fan-out with an external 2k pull-up resistor to +5V.
UC1526 UC2526 UC3526
Multiple devices can be synchronized together by programming one master unit for the desired frequency and then sharing its sawtooth and clock waveforms with the slave units. All CT terminals are connected to the CT pin _____ _ of the master, _____all SYNC terminals are likewise conand _ nected to the SYNC pin of the master. Slave RT terminals are left open or connected to VREF. Slave RD terminals may be either left open or grounded. Error Amplifier The error amplifier is a transconductance design, with an output impedance of 2M . Since all voltage gain takes place at the output pin, the open-loop gain/frequency characteristics can be controlled with shunt reactance to ground. When compensated for unity-gain stability with 100pF, the amplifier has an open-loop pole at 800Hz. The input connections to the error amplifier are determined by the polarity of the switching supply output voltage. For positive supplies, the common-mode voltage is +5.0V and the feedback connections in Figure 6A are used. With negative supplies, the common-mode voltage is ground and the feedback divider is connected between the negative output and the +5.0V reference voltage, as shown in Figure 6B. Output Drivers The totem-pole output drivers of the UC1526 are designed to source and sink 100mA continuously and 200mA peak. Loads can be driven either from the output pins 13 and 16, or from the +VC, as required. Since the bottom transistor of the totem-pole is allowed to saturate, there is a momentary conduction path from the +VC terminal to ground during switching. To limit the resulting current spikes a small resistor in series with pin 14 is always recommended. The resistor value is determined by the driver supply voltage, and should be chosen for 200mA peak currents.
Figure 4. Digital Control Port Schematic Oscillator The oscillator is programmed for frequency and dead time with three components: RT, CT and RD. Two waveforms are generated: a sawtooth waveform at pin 10 for pulse width modulation, and a logic clock at pin 12. The following procedure is recommended for choosing timing values: 1. With RD = 0 (pin 11 shorted to ground) select values for RT and CT from Figure 7 to give the desired oscillator period. Remember that the frequency at each driver output is half the oscillator frequency, and the frequency at the +VC terminal is the same as the oscillator frequency. 2. If more dead time is required, select a large value of RD. At 40kHz dead time increases by 400ns/ . 3. Increasing the dead time will cause the oscillator frequency to decrease slightly. Go back and decrease the value of RT slightly to bring the frequency back to the nominal design value. The UC1526 can be synchronized to an external logic clock by programming the oscillator to free-run at a frequency 10% slower than the sync frequency. A periodic _____ _ LOW logic pulse approximately 0.5s wide at the SYNC pin will then lock the oscillator to the external frequency.
Figure 5. Oscillator Connections and Waveforms
5
UC1526 UC2526 UC3526
Figure 6. Error Amplifier Connections
Figure 8. Single-Ended Configuration
Figure 7. Push-Pull Configuration
Figure 9. Driving N-channel Power Mosfets
TYPICAL CHARACTERISTICS
Oscillator Period vs RT and CT
Oscillation Period 6
UC1526 UC2526 UC3526 TYPICAL CHARACTERISTICS
Output Driver Deadtime vs RD Value Under Voltage Lockout Characteristic
Error Amplifier Open Loop Gain vs Frequency
Current Limit Transfer Function
Shutdown Delay
Output Driver Saturation Voltage
UNITRODE INTEGRATED CIRCUITS 7 CONTINENTAL BLVD. * MERRIMACK, NH 03054 TEL. (603) 424-2410 * FAX (603) 424-3460
7
PACKAGE OPTION ADDENDUM
www.ti.com
27-Sep-2005
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 2
PACKAGE OPTION ADDENDUM
www.ti.com
18-Oct-2005
PACKAGING INFORMATION
Orderable Device 85515012A 8551501VA UC1526J UC1526J883B UC1526L UC1526L883B UC2526J UC2526N UC2526NG4 UC3526DW UC3526DWG4 UC3526DWTR UC3526DWTRG4 UC3526J UC3526N UC3526NG4
(1)
Status (1) ACTIVE ACTIVE ACTIVE ACTIVE ACTIVE ACTIVE ACTIVE ACTIVE ACTIVE ACTIVE ACTIVE ACTIVE ACTIVE ACTIVE ACTIVE ACTIVE
Package Type LCCC CDIP CDIP CDIP LCCC LCCC CDIP PDIP PDIP SOIC SOIC SOIC SOIC CDIP PDIP PDIP
Package Drawing FK J J J FK FK J N N DW DW DW DW J N N
Pins Package Eco Plan (2) Qty 20 18 18 18 20 20 18 18 18 18 18 18 18 18 18 18 1 1 1 1 1 1 1 20 20 40 40 TBD TBD TBD TBD TBD TBD TBD Green (RoHS & no Sb/Br) Green (RoHS & no Sb/Br) Green (RoHS & no Sb/Br) Green (RoHS & no Sb/Br)
Lead/Ball Finish
MSL Peak Temp (3)
POST-PLATE Level-NC-NC-NC A42 SNPB A42 SNPB A42 SNPB Level-NC-NC-NC Level-NC-NC-NC Level-NC-NC-NC
POST-PLATE Level-NC-NC-NC POST-PLATE Level-NC-NC-NC A42 SNPB CU NIPDAU CU NIPDAU CU NIPDAU CU NIPDAU CU NIPDAU CU NIPDAU A42 SNPB CU NIPDAU CU NIPDAU Level-NC-NC-NC Level-NC-NC-NC Level-NC-NC-NC Level-2-260C-1 YEAR Level-2-260C-1 YEAR Level-2-260C-1 YEAR Level-2-260C-1 YEAR Level-NC-NC-NC Level-NC-NC-NC Level-NC-NC-NC
2000 Green (RoHS & no Sb/Br) 2000 Green (RoHS & no Sb/Br) 1 20 20 TBD Green (RoHS & no Sb/Br) Green (RoHS & no Sb/Br)
The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS) or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
Addendum-Page 1
PACKAGE OPTION ADDENDUM
www.ti.com
18-Oct-2005
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 2
IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI's terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI's standard warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and applications using TI components. To minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards. TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI. Reproduction of information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for such altered documentation. Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not responsible or liable for any such statements. Following are URLs where you can obtain information on other Texas Instruments products and application solutions: Products Amplifiers Data Converters DSP Interface Logic Power Mgmt Microcontrollers amplifier.ti.com dataconverter.ti.com dsp.ti.com interface.ti.com logic.ti.com power.ti.com microcontroller.ti.com Applications Audio Automotive Broadband Digital Control Military Optical Networking Security Telephony Video & Imaging Wireless Mailing Address: Texas Instruments Post Office Box 655303 Dallas, Texas 75265 Copyright 2005, Texas Instruments Incorporated www.ti.com/audio www.ti.com/automotive www.ti.com/broadband www.ti.com/digitalcontrol www.ti.com/military www.ti.com/opticalnetwork www.ti.com/security www.ti.com/telephony www.ti.com/video www.ti.com/wireless

▲Up To Search▲

Price & Availability of UC2526Q

	To Download UC2526Q Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .