VIPER22A SMPS Controller IC

9 July 2019 - 0 Comments

VIPER22A SMPS Controller IC

VIPER22A Pinout

The VIPER22A is a Popular SMPS controller IC form STMicroelectronics that has been extensively used in AC to DC Converters in offline power circuit designs. This controller IC consists of an in-built PWM controller with a power MOSFET. The MOSFET is connected to the primary side a power transformer which when switched will produce the required output voltage based on transformer design.

Pin Configuration

Pin Number	Pin Name	Description
1,2	Source	Source pin of the switching MOSFET
3	Feedback	Feedback for the SMPS circuit
4	VDD	Vdd voltage 9V to 38V
5,6,7,8	Drain	Drain pin of the switching MOSET

VIPER22A Specifications

SMPS Switching Controller IC
AC to DC converter
Operating Voltage: 9V to 38V
Oscillator Frequency: 60 kHz typically
Mosfet Drain to Source Voltage: 730V
Off state drain current: 0.1mA
Rise time and Fall time 50ns and 100ns respectively
Available in PDIP and SO 8-pin package

Equivalent for VIPER22A: VIPER12A, AP8012

Other Switching Regulators: LM2596, LM2576

Introduction to Viper22A

The Viper22A is popular SMPS buck controller device from the ViperXX series of ST Microelectronics. The controller can convert AC voltage from 85V to 265V and convert it to regulated DC voltage, it is commonly used as a replacement for transformer less power supply circuits. The IC is a combination of a PWM controller and a power mosfet and can work as a efficient AC to DC converter with very few external components. The below circuit is a sample application circuit for the Viper22A controller IC

VIPER22A SMPS Controller Circuit Diagram

The output voltage and current depends on the design of the transformer and the value of capacitor and inductor chosen for the circuit. The IC is known for its simplicity and minimum number of components required by it to function as an AC to DC converter for transformer less power supply circuits. As you can see on the above application circuit, the transformer plays an important role in the whole design with three coils namely the primary, secondary and the auxiliary (the 2nd coil on the primary side) . The primary side of the transformer is connected to the rectified mains voltage through the mosfet in our Viper controller IC, this mains DC will be switching based on the feedback given to the IC. The auxiliary coil of the transformer is used to power the Viper IC and the secondary side of the transformer provides the required output voltage.