Controller IC SCM1725A with High Power Density And Fast Startup Function for Smart Meter Industry


Introduction of Controller IC SCM1725A

Due to the widespread application of smart meters in the power grid, MORNSUN launched a controller IC SCM1725A with high power density, fast response, and good price-performance for this application.

The SCM1725A is a current mode PWM controller IC integrating a 2A power MOSFET with a minimum withstand voltage of 650V in the drain. By connecting the power bus voltage directly, the high-voltage startup pin can achieve the fast charging of the VDD bypass capacitor. At the same time, after the SCM1725A starts short-circuit protection, the VDD capacitor voltage can drop to the VDD under-voltage point, and fast startup circuit at the high-voltage restarts to charge the VDD bypass capacitor until the VDD startup voltage is reached, then the startup circuit stops working and reduces losses.

Controller IC SCM1725A has good efficiency performance because of the built-in frequency jitter mode at light-load. At the same time, it also has built-in duty-cycle slope compensation, internal loop compensation, and other circuits to achieve a stable system loop operation. In order to improve system reliability, a series of protection are also integrated inside the SCM1725A. In addition, it integrates the EN pin by connecting a logic high level to enter a very low power mode and the VDD pin voltage is kept at about 8.6V. If the SCM1725A has sufficient heat dissipation conditions, the output peak power will reach up to 20W when it is turned on / off intermittently at 3S in an open 75 ° C environment.

Application of Controller IC SCM1725A

It can be widely used in the smart meter system, non-isolated AC / DC power supply, and other fields.

Typical application circuit 1:

 (MORNSUN can provide matched controller IC and transformer)


Typical application circuit 2:

(MORNSUN can provide matched controller IC and transformer)


Features of Controller IC SCM1725A

Built-in 2A power MOSFET with a minimum withstand voltage of 650V

● Built-in VDD quick start function

● Frequency Reduction at Light Load and Burst Mode Control under no load

● The fixed maximum operating frequency of 120kHz and built-in frequency jitter function

● Built-in slope compensation

● Current limit per cycle

● Current mode control

● Built-in soft start

● VDD over-voltage protection (OVP), VDD under-voltage lockout (UVLO), open-loop and output short-circuit protection

● Chip power consumption is less than 20μA in turn-off mode

● Peak power up to 20W

Please refer to the technical manual for specific product parameters:

Series Power(W) Package Topology Control Mode Vds(max)(V) HV Fsw(khz) OTP OVP OCP Datasheet Sample
SCM1725A ≤20 SOP-7 Flyback - - 120 Built-in Built-in Built-in SCM1725A


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