Overview
The STCH02TR, produced by STMicroelectronics, is an offline PWM quasi-resonant controller designed specifically for ultra-low standby power supplies. This IC is optimized for high efficiency and ultra-low standby consumption, making it an ideal choice for building power supplies with excellent overall and dynamic performances. The STCH02TR combines a high-performance low-voltage PWM controller chip and a 650 V high-voltage start-up cell in the same SO-8 package.
Key Specifications
| Parameter | Min. | Typ. | Max. | Unit |
|---|---|---|---|---|
| VHV (High Voltage) | -0.3 | - | 650 | V |
| HVSTART (HV Start Voltage) | 40 | 50 | 60 | V |
| ICHARGE (VDD Start-up Charge Current) | 0.3 | 0.6 | 0.9 | mA |
| VDD (Supply Voltage Operating Range) | 11.5 | - | 23 | V |
| TJ (Junction Temperature Range) | -40 | - | 150 | °C |
| TSTG (Storage Temperature) | -55 | - | 150 | °C |
| Maximum Switching Frequency | - | - | 260 kHz | - |
Key Features
- Advanced power management for ultra-low standby power consumptions (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
- Automatic self-supply
- Accurate and adjustable output overvoltage protection (OVP) with autorestart after fault
- Input voltage feedforward compensation for mains-independent CC regulation
- Intelligent frequency jitter for EMI suppression
- SO-8 package
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
Q & A
- What is the primary function of the STCH02TR?
The STCH02TR is an offline PWM quasi-resonant controller designed for ultra-low standby power supplies, particularly for high-efficiency and low-standby consumption applications.
- What is the maximum voltage the HV pin can withstand?
The HV pin can withstand up to 650 V.
- How does the STCH02TR achieve quasi-resonant operation?
The quasi-resonant operation is achieved by synchronizing the MOSFET's turn-on to the transformer's demagnetization, detected by the negative-going edge of the voltage across any winding of the transformer.
- What are the different operating modes of the STCH02TR?
The device operates in QR mode at heavy load, valley-skipping mode at medium/light load, and burst mode at very light or no load.
- How does the STCH02TR reduce EMI emissions?
The device reduces EMI emissions through intelligent frequency jittering and by operating close to zero voltage switching (ZVS) conditions.
- What is the purpose of the high-voltage start-up circuit?
The high-voltage start-up circuit allows the IC to start up using a 7 mA internal current source when the voltage on the HV pin reaches the HVSTART voltage, ensuring continuous operation even without an auxiliary winding.
- What is the significance of the VDD foldback threshold?
The VDD foldback threshold ensures that the IC's operation is adjusted based on the supply voltage, helping in maintaining stable operation and preventing overvoltage conditions.
- How does the STCH02TR handle overvoltage protection?
The device features accurate and adjustable output overvoltage protection (OVP) with autorestart after fault, ensuring safe operation and automatic recovery from fault conditions.
- What is the typical package type for the STCH02TR?
The STCH02TR is available in an SO-8 package.
- What are some common applications of the STCH02TR?
Common applications include AC-DC chargers for handheld devices, AC/DC adapters for set-top boxes and notebooks, and auxiliary power supplies.
