12W Step Up DC-DC Converter using MAX1771
MAX1771 Step-Up Converter: 5V to 12V boost with 90% efficiency. Uses PFM for 1A output and ultra-low 110µA quiescent current.
This compact step-up DC-DC converter delivers up to 90% efficiency with load currents up to 1A. The design is based on the MAX1771, which uses a unique current-limited Pulse Frequency Modulation (PFM) control scheme. This architecture combines the high efficiency of traditional PWM converters at heavy loads while consuming less than 110µA supply current, significantly lower than the 2mA to 10mA typically required by PWM-based designs.
The converter operates with miniature external components, and its high switching frequency of up to 300kHz allows the use of compact surface-mount magnetics with approximately 5mm height and 9mm diameter. The circuit accepts a 5V input supply and provides a pre-set 12V output. The output voltage can also be adjusted using external resistor divider components R2 and R4.
The MAX1771 is optimised for high efficiency at low input voltages and reduced output noise by maintaining a constant 100mV current-limit threshold across varying load conditions. An external N-channel MOSFET is used as the power switch, enabling the converter to deliver output power up to 12W.
Features
- Power Input 5V DC
- Output 12V DC
- Output Current 500mA (Up to 1Amp with Proper Cooling)
- Screw Terminal Connector for Input and Output
- Operating Frequency 300Khz
- Efficiency 90%
- Output LED
- 4 x 3MM PCB Mounting Holes
- PCB Dimensions: 36.20 x 34.93 mm
Connections
- CN1: Pin 1 = Power Input 5V DC, Pin 2 = GND
- CN2: Pin 1 = Power Output 12V DC, Pin 2 = GND
- D2: Output Power LED
Schematic
Parts List
| NO | QNTY. | REF. | DESC. | MANUFACTURER | SUPPLIER | SUPPLIER PART NO |
|---|---|---|---|---|---|---|
| 1 | 2 | CN1,CN2 | 2 PIN SCREW TERMINAL PITCH 5.08MM | PHOENIX | DIGIKEY | 277-1247-ND |
| 2 | 1 | C1 | 100uF/16V TANTLUM | KYOCERRA AVX | DIGIKEY | 478-3919-1-ND |
| 3 | 1 | C2 | 100nF/50V CERAMIC SMD SIZE 0805 | DIGIKEY | ||
| 4 | 1 | C3 | 330uF/16V ELECTROLYTIC | NICHICON | DIGIKEY | 493-2180-1-ND |
| 5 | 1 | C4 | 100PF/50V CERAMIC SMD SIZE 0805 | MURATA/YAGEO | DIGIKEY | |
| 6 | 1 | C5 | 100nF/25V CERAMIC SMD SIZE 0603 | MURATA/YAGEO | DIGIKEY | |
| 7 | 1 | D1 | MBRS340 | ONSEMI | DIGIKEY | MBRS340FSTR-ND |
| 8 | 1 | D2 | LED SMD SIZE 0805 | OSRAM | DIGIKEY | 475-1278-1-ND |
| 9 | 1 | L1 | 22uH/3A | BOURNS INC | DIGIKEY | 118-PM124SH-220M-RCCT-ND |
| 10 | 1 | Q1 | IRFR024 | INFINEON | DIGIKEY | IRFR024NPBFCT-ND |
| 11 | 1 | R1 | 2K 1% SMD SIZE 0805 | MURATA/YAGEO | DIGIKEY | |
| 12 | 1 | R2 | 127K 1% SMD SIZE 0805 | MURATA/YAGEO | DIGIKEY | |
| 13 | 1 | R3 | 0.04E/1W 1% SMD SIZE 2512 | YAGEO | DIGIKEY | YAG2155CT-ND |
| 14 | 1 | R4 | 18K 1% SMD SIZE 0805 | MURATA/YAGEO | DIGIKEY | |
| 15 | 1 | U1 | MAX1771 SOIC8 | ANALOG DEVICE | DIGIKEY | MAX1771CSA+CT-ND |
Connections
Gerber View
Photos
