## STMicroelectronics VIPER113LS Overview The **VIPER113LS** is a high-voltage converter belonging to the VIPerPlus family. It is specifically designed for smart power supplies and low-power offline Switch Mode Power Supplies (SMPS). It integrates an 800 V avalanche-rugged power MOSFET with PWM current mode control. ### Key Electronic Specifications | Parameter | Value / Range | | :--- | :--- | | **Drain-Source Voltage ($V_{DSS}$)** | 800 V (Minimum) | | **Switching Frequency** | 60 kHz (fixed) | | **Integrated MOSFET $R_{DS(on)}$** | 13 $\Omega$ (Typical) | | **Supply Voltage ($V_{CC}$)** | 4.5 V to 30 V | | **Max Output Power** | ~5W (Wide range) / ~8W (European range) | | **Package Type** | SSOP10 | --- ### Core Internal Components 1. **800 V Power MOSFET**: The high breakdown voltage allows the chip to withstand significant voltage spikes from the AC line without the need for complex snubber circuits in many cases. 2. **High Voltage Startup**: It features an internal high-voltage current source. This eliminates the need for external startup resistors, reducing standby power consumption. 3. **PWM Controller**: Operates in current mode with a fixed frequency of 60 kHz. It includes "Frequency Jittering" to reduce EMI (Electromagnetic Interference) emissions. 4. **Error Amplifier**: Includes an integrated transconductance error amplifier with a 1.2 V reference, allowing for direct feedback without an external shunt regulator in some topologies. --- ### Functional Protection Features The VIPER113LS is "fully protected," meaning it includes several safety mechanisms to prevent circuit failure: * **Pulse-by-Pulse Current Limiting**: Protects the MOSFET from overcurrent on every switching cycle. * **Hysteretic Thermal Shutdown**: Shuts the device down if the junction temperature exceeds ~150°C. * **Overvoltage Protection (OVP)**: Monitors $V_{CC}$ to prevent damage from voltage spikes. * **Short Circuit Protection**: Detects output shorts and enters a "hiccup" mode to lower power dissipation until the fault is removed. --- ### Typical Application Circuit The device is most commonly used in **Non-Isolated Flyback** or **Buck** converters. ```mermaid graph LR AC_Input --> Bridge_Rectifier Bridge_Rectifier --> Filter_Capacitor Filter_Capacitor --> Transformer/Inductor Transformer/Inductor --> VIPER113LS VIPER113LS --> Feedback_Loop Feedback_Loop --> DC_Output ``` ### Advantages for Design * **Low Standby Power**: Consumes less than 10 mW at 230 $V_{AC}$ in no-load conditions. * **Reduced BOM**: Integrated startup, error amp, and MOSFET reduce the total Bill of Materials. * **Robustness**: The 800 V rating provides a high safety margin for unstable power grids.