The **VIPER100A-E** (often referred to in its package variants like VIPER100ASPTR) is a high-performance **Offline Switched-Mode Power Supply (SMPS) Primary Switcher**. It belongs to the VIPer (Vertical Intelligent Power) family developed by STMicroelectronics. It integrates a dedicated current-mode PWM controller with a high-voltage Power MOSFET on the same silicon chip. --- ## 1. Key Component Specifications | Parameter | Specification | | :--- | :--- | | **Drain-Source Voltage ($V_{DSS}$)** | 700 V | | **Output Current ($I_D$)** | 3.5 A | | **Switching Frequency** | Up to 200 kHz (Adjustable) | | **Supply Voltage ($V_{DD}$)** | 8 V to 15 V | | **Package Types** | PENTAWATT, PowerSO-10 (Surface Mount) | --- ## 2. Pin Configuration and Functions The VIPER100A typically utilizes the following functional pins to manage power conversion: 1. **DRAIN**: Connected to the internal MOSFET drain. It is typically connected to the primary winding of the transformer. 2. **SOURCE**: Ground reference for the internal control circuit and the MOSFET source. 3. **VDD**: Control circuit power supply. It usually features an internal high-voltage start-up current source. 4. **COMP**: Input for the feedback loop. It adjusts the duty cycle based on the output voltage requirements. 5. **OSC**: Pin used to set the operating frequency using an external RC network. --- ## 3. Internal Functional Blocks The "Intelligence" of the VIPER100A comes from its integrated sub-systems: * **High Voltage Startup**: Allows the chip to draw initial power directly from the rectified AC line, eliminating the need for bulky external bleed resistors. * **Current Mode Control**: Provides inherent cycle-by-cycle current limiting and improved loop stability. * **Thermal Shutdown**: An internal sensor shuts down the device if the junction temperature exceeds approximately 170°C to prevent catastrophic failure. * **Burst Mode Operation**: Enhances efficiency during light load conditions by skipping switching cycles, reducing "standby" power consumption. --- ## 4. Typical Application Diagram In a standard Flyback converter, the VIPER100A simplifies the BOM (Bill of Materials) significantly: ```mermaid graph LR AC_Input --> Rectifier Rectifier --> Transformer_Primary Transformer_Primary --> VIPER100A_Drain VIPER100A_Source --> GND Optocoupler --> VIPER100A_Comp ``` ### Advantages * **Reduced Component Count**: No need for separate PWM ICs and Power MOSFETs. * **Robustness**: 700V breakdown voltage provides a high safety margin against voltage spikes. * **Frequency Modulation**: The ability to adjust frequency helps in optimizing EMI (Electromagnetic Interference) signatures. ---