Overview
The STCH03TR, produced by STMicroelectronics, is an offline PWM controller designed for quasi-resonant ZVS (zero-voltage-switching at switch turn-on) flyback converters. This device combines a high-performance low-voltage PWM controller chip and a 650V HV start-up cell in the same package, enabling advanced power management with ultra-low standby power consumption.
The STCH03TR features constant output voltage (CV) regulation through secondary side feedback and constant output current regulation (CC) using primary-sensing feedback, eliminating the need for dedicated current reference ICs and current sensors. It also includes quasi-resonant operation, achieved through transformer demagnetization sensing, and various protection mechanisms such as overvoltage protection (OVP), overtemperature protection (OTP), and undervoltage protection (UVP).
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| VHV Voltage Range | -0.3 to 650 | V |
| VDD Operating Range | 11.5 to 23 | V |
| VDD Turn-on Threshold | 15.7 to 18.3 | V |
| Maximum Switching Frequency | 154 kHz | kHz |
| Junction Temperature Range | -40 to 150 | °C |
| Package | SO-8 | |
| Quiescent Current (Burst Operation) | 290 to 335 μA | μA |
| Thermal Shutdown Temperature | 135 to 165 | °C |
Key Features
- Advanced power management for ultra-low standby power consumption (under 10 mW at 230 VAC)
- Fully integrated primary side constant current output regulation (CC)
- 650 V embedded HV start-up circuit with zero power consumption
- Quasi-resonant (QR) zero-voltage-switching (ZVS) operation
- Accurate and adjustable output OVP with options for auto-restart or latched mode after fault
- Output undervoltage protection (UVP) with auto-restart
- Input voltage feedforward compensation for mains-independent CC regulation
- Embedded thermal shutdown
- Intelligent frequency jitter for EMI suppression
- Leading-edge blanking on the current sense input for greater noise immunity
Applications
- AC-DC chargers for smartphones, tablets, camcorders, and other handheld equipment
- AC/DC adapters for set-top boxes (STB), notebooks, and auxiliary power supplies
- USB power delivery fast chargers
- Industrial and personal electronics
Q & A
- What is the primary function of the STCH03TR?
The STCH03TR is an offline PWM controller designed for quasi-resonant ZVS flyback converters, providing advanced power management and constant output current regulation.
- What is the maximum switching frequency of the STCH03TR?
The maximum switching frequency is top-limited below 154 kHz.
- How does the STCH03TR achieve quasi-resonant operation?
Quasi-resonant operation is achieved through transformer demagnetization sensing input that triggers the turn-on of the MOSFET.
- What protection mechanisms are included in the STCH03TR?
The device includes overvoltage protection (OVP), overtemperature protection (OTP), undervoltage protection (UVP), and hiccup-mode protection.
- What is the package type of the STCH03TR?
The STCH03TR is packaged in an SO-8 package.
- What is the quiescent current in burst-mode operation?
The quiescent current in burst-mode operation is between 290 to 335 μA.
- How does the STCH03TR manage thermal issues?
The device features embedded thermal shutdown with a temperature range of 135 to 165 °C.
- What are the typical applications of the STCH03TR?
Typical applications include AC-DC chargers, AC/DC adapters, and USB power delivery fast chargers.
- How does the STCH03TR optimize power handling under different operating conditions?
The device optimizes power handling through controlled burst-mode operation, zero-power high-voltage start-up circuit, and extremely low quiescent current.
- What is the role of the adaptive UVLO in the STCH03TR?
The adaptive UVLO helps minimize issues related to fluctuations of the auxiliary biasing voltage, reducing the IC's bias consumption.
