DatasheetsPDF.com

UC3827-2 Dataheets PDF



Part Number UC3827-2
Manufacturers Texas Instruments
Logo Texas Instruments
Description BUCK CURRENT/VOLTAGE FED PUSH-PULL PWM CONTROLLERS
Datasheet UC3827-2 DatasheetUC3827-2 Datasheet (PDF)

UC2827-1, UC2827-2 UC3827-1, UC3827-2 www.ti.com SLUS365D – APRIL 1999 – REVISED APRIL 2011 BUCK CURRENT/VOLTAGE FED PUSH-PULL PWM CONTROLLERS Check for Samples: UC2827-1, UC2827-2, UC3827-1, UC3827-2 FEATURES 1 • Ideal for Multiple Output and/or High Voltage Output Voltage Converters • Up to 500 kHz Operation • High Voltage, High Current Floating Driver for Buck Converter Stage • UC3827-1 Current Fed Controller has Push-Pull Drivers with Overlapping Conduction Periods • UC3827-2 Voltage Fed .

  UC3827-2   UC3827-2


Document
UC2827-1, UC2827-2 UC3827-1, UC3827-2 www.ti.com SLUS365D – APRIL 1999 – REVISED APRIL 2011 BUCK CURRENT/VOLTAGE FED PUSH-PULL PWM CONTROLLERS Check for Samples: UC2827-1, UC2827-2, UC3827-1, UC3827-2 FEATURES 1 • Ideal for Multiple Output and/or High Voltage Output Voltage Converters • Up to 500 kHz Operation • High Voltage, High Current Floating Driver for Buck Converter Stage • UC3827-1 Current Fed Controller has Push-Pull Drivers with Overlapping Conduction Periods • UC3827-2 Voltage Fed Controller has Push-Pull Drivers with Nonoverlapping Conduction Periods • Average Current Mode, Peak Current Mode or Voltage Mode with Input Voltage Feedforward Control for Buck Power Stage • Wide Bandwidth, Low Offset, Differential Current Sense Amplifier • Precise Short Circuit Current Control DESCRIPTION The UC3827 family of controller devices provides an integrated control solution for cascaded buck and push-pull converters. These converters are known as current fed or voltage fed push-pull converters and are ideally suited for multiple output and/or high voltage output applications. In both current fed and voltage fed modes, the push-pull switches are driven at 50% nominal duty cycles and at one half the switching frequency of the buck stage. In the current fed mode, the two switches are driven with a specified over-lap period to prevent ringing and voltage stress on the devices. In the voltage fed mode, the two switches are driven with a specified gap time between the switches to prevent shorting the transformer across the energy storage capacitor and to prohibit excessive currents flowing through the devices. The converter's output voltage is regulated by pulse width modulation of the buck switch. The UC3827 contains complete protection and PWM control functions for the buck converter. Easy control of the floating switch is accomplished by the floating drive circuitry. The gate drive waveform is level shifted to support an input voltage up to 72 VDC. BLOCK DIAGRAM VEAOCEA+ CEAO 10 Voltage Error Amplifier VEA+ 14 12 6 VEA− 16 Current Error Amplifier CEA− 13 CSAO 7 CSA+ 8 CSA− 9 SS 4 SYNC 19 CT 18 RT 17 +3 V ILIM Comparator Current Sense Amplifier OSC SS INHBT UV 500 kHz MAX REF 15 + RAMP 5 0.7 V PWM Comparator RD SQ OSC Q DELAY T Q VCC 23 GND 11 REF & UVLO UVLO DELAY Flying Driver Push/Pull Drivers 20 DELAY 1 V+ 2 BUCK 3 SRC 21 PGND 24 PUSH 22 PULL 1 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 1999–2011, Texas Instruments Incorporated UC2827-1, UC2827-2 UC3827-1, UC3827-2 SLUS365D – APRIL 1999 – REVISED APRIL 2011 www.ti.com DESCRIPTION (CONTINUED) The UC3827 can be set up in traditional voltage mode control using input voltage feedforward technique or in current mode control. Using current mode control prevents potential core saturation of the push-pull transformer due to mismatches in timing and in component tolerances. With average current mode control, precise control of the inductor current feeding the push-pull stage is possible without the noise sensitivity associated with peak current mode control. The UC3827 average current mode loop can also be connected in parallel with the voltage regulation loop to assist only in fault conditions. Other valuable features of the UC3827 include bidirectional synchronization capability, user programmable overlap time (UC3827-1), user programmable gap time (UC3827-2), a high bandwidth differential current sense amplifier, and soft start circuitry. TA = TJ -40°C to 85°C 0°C to 70°C ORDERING INFORMATION(1) PUSH-PULL TOPOLOGY Current Fed Voltage Fed Current Fed Voltage Fed SOIC-24 UC2827DW-1 UC2827DW-2 UC3827DW-1 UC3827DW-2 PACKAGES PDIP-24 UC2827N-1 UC2827N-2 UC3827N-1 UC3827N-2 PLCC-28 - UC3827Q-1 - (1) The DW and Q packages are also available taped and reeled. Add a TR suffix to the device type (i.e., UC2827DWTR-1). THERMAL INFORMATION THERMAL METRIC UC2827-1, UC2827-2, UC3827-1, UC3827-2 UC2827-1, UC2827-2, UC3827-1, UC3827-2 UNITS NJ θJA θJCtop Junction-to-ambient thermal resistance(1) Junction-to-case (top) thermal resistance(2) 24 PINS 60 30 24 PINS 70 to 80 28 °C/W (1) The junction-to-ambient thermal resistance under natural convection is obtained in a simulation on a JEDEC-standard, high-K board, as specified in JESD51-7, in an environment described in JESD51-2a. (2) The junction-to-case (top) thermal resistance is obtained by simulating a cold plate test on the package top. No specific JEDEC-standard test exists, but a close description can be found in th.


UC3827-1 UC3827-2 UC2825A-EP


@ 2014 :: Datasheetspdf.com :: Semiconductors datasheet search & download site.
(Privacy Policy & Contact)