OB2238x is a high performance, high precision and low cost PWM Power switch for non-isolated buck and buck-boost application. It combines a dedicated current mode PWM controller with a high voltage power Mosfet in DIP8 package. Its built-in error amplifier is optimized for good overshoot and dynamic response for low cost and component count. With precise inner resistor divider, precise reference of EA constant voltage regulation of 18V at universal AC input can be guaranteed. Frequency reduction and burst mode control is implemented for high efficiency at light load. Good EMI performance is achieved with On-Bright proprietary frequency shuffling technique and soft gate driver design. Low startup current and low operating current contribute to a reliable power on startup and low standby power consumption with OB2238x.

OB2238x offers power on soft start control and protection coverage with auto-recovery features including cycle-by-cycle current limiting, output short circuit protection, on-chip Over Temperature Protection (OTP), VDD Over Voltage Protection (OVP), Over Loading Protection(OLP) and VDD Under Voltage Lockout Protection (UVLO).

The tone energy at below 20KHz is minimized in the design so that audio noise is eliminated during operation.

OB2238x is offered in DIP8 package.


·         Universal AC input range and 18V output voltage

·         Low cost and less BOM for buck  and buck-boost applications

·         Current mode control

·         40kHz (typical) maximum switching frequency

·         Frequency-reduction and burst mode control for high efficiency

·         Frequency shuffling for EMI improvement

·         Power on soft-start 

·         Built-in Leading Edge Blanking (LEB)

·         Cycle-by-cycle current limiting

·         Output short-circuit protection

·         VDD Under Voltage Lockout with Hysteresis

·         VDD OVP

·         Over Loading Protection

·         On-Chip OTP




Low power AC/DC offline SMPS for

·         Small home appliance

·         Linear regulator/RCC replacement