Summary of 230V AC INPUT – 12V OUTPUT DC CONVERTER, NON-ISOLATED BUCK CONVERTER
Summary: A non-isolated buck DC/DC converter converts 230V AC to 12V DC at up to 100 mA (max 150 mA). It uses the BM2P129TF PWM converter IC with a built-in 650V MOSFET, fixed 100 kHz switching (with light-load frequency reduction and frequency hopping for EMI), cycle-by-cycle current control, and onboard current detection for compact design. Efficiency is about 75% and PCB size is 46.67 x 19.53 mm.
Parts used in the 230V AC to 12V DC Converter:
- BM2P129TF PWM DC/DC converter IC (with built-in 650V MOSFET)
- Input rectifier (diode bridge)
- Input filter capacitor(s)
- High-voltage startup resistor/circuit (as part of supply to BM2P129TF)
- Switching inductor for buck conversion
- Output filter capacitor(s)
- Output load / connector providing up to 100mA (max 150mA)
- Current sense resistor (built-in detection or external as required)
- EMI suppression components (e.g., common-mode choke, capacitors)
- PCB (46.67 x 19.53 mm)
The project described here outputs 12V DC voltage from the input of 230V AC. The output current is up to 100mA. The project is based on BM2P129TF chip which is PWM method DC/DC converter with a built-in 650V MOSFET. BM2P129TF contributes to low power consumption by built-in a 650V starting circuit. Built-in current detection resistor realizes compact power supply design. Current mode control imposes current limitation on every cycle, providing superior performance in bandwidth and transient response. The switching frequency is 100Khz in fixed mode. At light load, frequency is reduced and high efficiency is realized. Built-in frequency hopping function contributes to low EMI. Low on-resistance 9.5 Ohms 650V MOSFET built-in contributes to low power consumption. The default over current limit of the chip is 450mA.
FEATURES
- Input Supply 230V AC
- Output 12V DC
- Load 100mA Constant (Maximum 150mA)
- Operating Frequency 100kHz Fixed
- Cycle By Cycle Current Control
- Efficiency 75%
- PCB Dimensions: 46.67 x 19.53 mm
Read more: 230V AC INPUT – 12V OUTPUT DC CONVERTER, NON-ISOLATED BUCK CONVERTER
- What is the input voltage for the project?
The input supply is 230V AC. - What is the output voltage and current capability?
The output is 12V DC with a constant load capability of 100mA and a maximum of 150mA. - Which main IC is used in the converter?
The converter is based on the BM2P129TF PWM DC/DC converter chip with a built-in 650V MOSFET. - What is the operating switching frequency?
The switching frequency is fixed at 100kHz, with frequency reduction at light load and built-in frequency hopping to reduce EMI. - How does the chip control current?
The BM2P129TF uses cycle-by-cycle current control and built-in current detection to limit current each switching cycle. - What is the efficiency of the power supply?
The efficiency is approximately 75%. - Does the converter include overcurrent protection?
The chip has a default over current limit of 450mA. - Is the design isolated from mains?
The project is a non-isolated buck converter. - What are the PCB dimensions?
The PCB dimensions are 46.67 x 19.53 mm.
