9V @ 45mA Boost Converter Output with Input 2.1V to 5.5V

Rajkumar Sharma
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SKU: EL134709
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The project shown here is a boost converter that provides 9V DC output from 2.1V to 5.5V input. It is a good choice for battery-operated devices where the converter can be connected to 2x 1.5V, 3 x 1.5V Battery, 1 x Li-ion, 2 x NICAD, 2 x NIMH, and provide 9V Output. The board is built using BD8158FVM chip and the pin configuration is the same as TO220 78xx LDO and the size is also the same. Output is very accurate and provides approx. 85% efficiency at an operating frequency of 1.2Mhz.

Features

Input 2.1V to 5.5V (2 X NIMH Battery, 2 X NICAD Battery, 1X Li-Ion Battery 3.6V, 2X AA/AAA battery)
3 Pin Header Pitch 2.54MM for Output and Input (Pin Configuration same as TO220 LDO Such as LM7805)
Output 9V DC
Output Current 45mA
85% Efficiency
Output Voltage +/-1%
Current Mode PWM System
Built-In Under-Voltage Lockout Protection Circuit
Built-In Over-Current Protection Circuit
Built-In Thermal Shutdown Circuit
PCB Dimensions 20.16 x 9.05mm

Protection Circuit (UVLO/TSD) UVLO (under-voltage lockout protection circuit) shuts down the circuit when the voltage is equal or lower than 1.8V. Thermal shutdown circuit shuts down IC’s operation at 175°C and recovers at 160°C.

Over-Current Protection Circuit (OCP) Current flowing to the power FET is detected by voltage at the CURRENT SENSE and the Over-Current protection operates at 3A. When the Over-Current protection activates, the switching is turned OFF and the SS pin capacity is discharged.

Soft-Start Circuit Since the output voltage rises gradually while restricting the current at the time of start-up, it is possible to prevent the output voltage overshoot or the inrush current.

Connections

CN1: Pin 1 = Input 2.1V to 5.5V, Pin 2 = GND, Pin 3 = Output 9V DC – 45mA

Schematic

Parts List

NO	QNTY	REF.	DESC	MANUFACTURER	SUPPLIER	SUPPLIER PART NO
1	1	CN1	3 PIN MALE HEADER RIGHT ANGLE PITCH 2.54MM	WURTH	DIGIKEY
2	1	C1	100PF/25V CERAMIC SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
3	1	C2	3.3nF/25V CERAMIC SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
4	1	C3	10nF/25V CERAMIC SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
5	1	C4	10uF/25V CERAMIC SMD SIZE 1206	MURATA/YAGEO	DIGIKEY
6	1	D1	SS34 SMD FAST SWITCHING DIODE	TAIWAN SEMI	DIGIKEY	1801-SS34TR-ND
7	1	L1	10uH/SMD 8MM	EATON	DIGIKEY	283-SDCH1V6028-100M-RCT-ND
8	1	R1	5.1K/1% SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
9	1	R2	110K/1% SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
10	1	R3	18K/1% SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
11	1	U1	BD8158FVM-TR	ROHM	DIGIKEY	BD8158FVMCT-ND
12	1	C5	10uF/25V CERAMIC SMD SIZE 0805	MURATA/YAGEO	DIGIKEY