Reference Design

A system-level evaluation board that combines ROHM's IC and discrete products. We have already solved not only the characteristics of individual products but also the problems that may occur when combining them to build a system, thus contributing significantly to the reduction of development time for our customers.

Non-Isolation Buck Converter PWM method Output 2 W 12 V Reference Design


The BM2P129T1F-EVK-001 evaluation board outputs 12 V voltage from the input of 90 Vac to 264 Vac. The output current supplies up to 0.167 A. BM2P129TF which is PWM method DC/DC converter IC built-in 650 V MOSFET is used.
The BM2P129TF contributes to low power consumption by built-in a 650 V 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 100 kHz 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 9.5Ω 650V MOSFET built-in contributes to low power consumption and easy design.


Reference Board NameBM2P129TF-EVK-001
Input Voltage Range90to264 Vac
Input Frequency47to63Hz
Output Voltage12.0V(Typ)
Maximum Output Power2.0W (Max)Iout=167mA 
Output Current Range2to167mA*1
Stand-by Power30mW Iout=0A
Efficiency76.1% Iout=167mA
Output Ripple Voltage38mVpp*2
Operating Temperature-10 to 65deg.C

*1 Please adjust operating time, within any parts surface temperature under 105 °C
*2 Not include spike noise


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Calc toolEVK, Eval board for individual product

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