The **VIPER100** is a high-voltage power conversion IC developed by STMicroelectronics. It belongs to the VIPer (Vertical Intelligent Power) family, which integrates a dedicated PWM (Pulse Width Modulation) controller with a high-voltage Power MOSFET on the same silicon chip. --- ## 1. Core Component Breakdown The VIPER100 is essentially a "System-on-Chip" for switched-mode power supplies (SMPS). It consists of two primary sections: | Part | Description | Function | | :--- | :--- | :--- | | **Power MOSFET** | N-Channel Power Transistor | Handles high voltage (up to 700V) and switches current through the transformer. | | **Control Circuit** | PWM Controller + Logic | Manages the switching frequency, duty cycle, and protective features. | --- ## 2. Technical Specifications Below are the key electrical characteristics of the VIPER100: | Parameter | Value | | :--- | :--- | | **Drain-Source Voltage ($V_{DSS}$)** | 700V | | **Output Power** | Up to 100W (Wide range 85-265 VAC) | | **Switching Frequency** | Adjustable up to 200 kHz | | **Package** | PENTAWATT HV / PowerSO-10 | | **On-Resistance ($R_{DS(on)}$)** | ~2.5 $\Omega$ | --- ## 3. Internal Functional Blocks The VIPER100 includes several critical sub-circuits to ensure efficient power delivery and safety: ### A. Current Sense & PWM The IC uses **current mode control**. It monitors the current flowing through the MOSFET in each cycle. This allows for better stability and faster response to load changes compared to voltage-mode control. ### B. High Voltage Startup The chip features an internal high-voltage current source. When power is first applied, this source charges an external capacitor to start the IC, eliminating the need for bulky external "bleeder" resistors. ### C. Protection Features * **Thermal Shutdown:** If the junction temperature exceeds 150°C, the IC shuts down to prevent melting. * **Overcurrent Protection:** Limits the maximum peak current to protect the transformer and MOSFET. * **Undervoltage Lockout (UVLO):** Ensures the device only operates when the supply voltage is high enough to drive the MOSFET gate properly. --- ## 4. Typical Application Circuit In a standard Flyback converter, the VIPER100 pins are utilized as follows: ```text Pin 1: DRAIN -> Connected to the Primary winding of the transformer. Pin 2: SOURCE -> Connected to Ground (Primary side). Pin 3: VDD -> Power supply for the control logic (via auxiliary winding). Pin 4: COMP -> Input for the feedback loop (Optocoupler). Pin 5: OSC -> External RC network to set switching frequency. ``` --- ## 5. Summary of Benefits * **Reduced Component Count:** Integrates the power switch and controller. * **Safety:** High breakdown voltage (700V) provides a large margin for voltage spikes. * **Efficiency:** Features "Burst Mode" operation during light loads to save energy.