High Current Half-Bridge with Over Current & Voltage Feedback for Step Down DC-DC Converter

  • Rajkumar Sharma
  • 66 Views
  • medium
  • Tested
  • SKU: EL121012
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This project enables the user to create a high current DC-DC converter. The project consists of a high current inductor, high current low voltage 2 x MOSFETs, half-bridge driver LT1158 chip, voltage feedback using onboard R9 and R10 resistor dividers, shunt resistor for overcurrent shut-down. The project has all the required components to create a high current step-down DC-DC converter, refer to the datasheet of LT1158 chip for components selection. The Half-bridge requires a PWM input signal, Arduino or another microcontroller/DSP can be used as a host to generate PWM signal and control enable and fault conditions.

Arduino Example Code helps users to test the board, the project provides output approx. 5V/4Amps from input Supply 22-24V DC.

Applications

  • DC-DC Converter
  • High Current Solar Charger
  • SLA Battery Charger

Key Features

  • High Current Low Voltage 2 x MOSFET IRF540 (the user may Use Other Low Ohm MOSFET)
  • Half-Bridge Driver LT1158 Chip
  • L1 High Current Inductor Default 100uH/7.8Amp
  • R2 and R3 Resistor for Current Sense, For Over Current Limit/Short Circuit – Refer to Datasheet for R2, R3 Values.
  • Fault: Open collector NPN output which turns on when V12 – V11 (Current Sense Pins) exceeds the fault conduction threshold.
  • D3 LED for Output, D2 LED for Input Supply
  • Voltage Feedback Output CN5, Resistor Divider R9, R10, C11
  • Inputs and Fault Output CN2
  • Operating Supply 12V to 30V DC (Input Supply Should Not Exceed 30V)
  • PCB Dimensions 69.22 x 55.88 mm

Over Current Shutdown – Open collector, NPN output turns on when V12 – V11 (Current Sense Pins) exceeds the fault conduction threshold.

  • For Internal Over Current Shutdown Use R7 and C8, Refer to Datasheet for Values
  • For Host Controlled Shutdown Use Fault and Enable Pins

Voltage Feedback

  • CN5, Feedback from Output using Resistor Divider R9 and R10, Use C11 for stability.

Connections: CN2

  • Pin1 = VCC
  • Pin2 = Enable – Pull Low to disable the Output
  • Pin3= Fault Output – Goes Low when Over Current Condition Occurs
  • Pin4= PWM Input 0 to 100Khz
  • Pin5=GND
  • Use R7 and C8 for Internal Over Current Shutdown, Refer to Datasheet of LT1158

Connections CN1

  • Pin1 = VCC 12V to 30V Input
  • Pin2 + GND

Connections CN3

  • Pin1 = + Output
  • Pin2= GND

CN4: Not Installed

Connections CN5

  • Pin 1 = +Voltage Feedback Output
  • Pin 2 = GND

Schematic

Parts List

NOQNTY.REF.DESC.MANUFACTURERSUPPLIERPART NO
12CN1,CN32 PIN BARRIER BLOCK PITCH 9.53MMTE CONNECTIVITYDIGIKEYA98481-ND
21CN25 PIN MALE HEADER PITCH 2.54MMWURTHDIGIKEY732-5318-ND
310R4,CN4,CN5,C6,R7DNPREAD NOTE
C8,R9,R10,C10,C11DNPREAD NOTE
42C3,C70.1uF/50V SMD SIZE 0805MURATA/YAGEODIGIKEY
51C210uF/35VDIGIKEY
61C41000uF/35VRUBYCONDIGIKEY1189-1745-ND
71C50.01uF/50V SMD SIZE 0805MURATA/YAGEODIGIKEY
81C91000uF/25VEPCOSDIGIKEY495-6061-ND
91D11N4148MICROCHIPDIGIKEY1N4148UR-1-ND
102D2,D3LED SMD SIZE 0805OSRAMDIGIKEY475-1278-1-ND
111L1100uH/7.8AMPBOURNS INCDIGIKEY2300LL-101-V-RC-ND
122Q1,Q2IRF540VISHAYDIGIKEYIRF540IR-ND
132R1,R50E SMD SIZE 0805MURATA/YAGEODIGIKEY
141R2DNP
151R30.025E 1% SMD SIZE 0805YAGEODIGIKEYYAG2169CT-ND
161R63K3 5% SMD SIZE 1206MURATA/YAGEODIGIKEY
171R81K 5% SMD SIZE 0805MURATA/YAGEODIGIKEY
181R11330K 5% SMD SIZE 0805MURATA/YAGEODIGIKEY
191U1LT1158ANALOG DEVICEDIGIKEYLT1158CSW#TRPBFTR-ND
201C10.1uF/50V SMD SIZE 1206MURATA/YAGEODIGIKEY

Connections



Gerber View

Photos

Video


LT1158 Datasheet

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PCB

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