Overview
The ALTAIR04-900TR from STMicroelectronics is a high-voltage, all-primary-sensing switching regulator designed for off-line quasi-resonant flyback converters. This device integrates a low-voltage PWM controller and a 900 V avalanche-rugged power section in a single package. It operates directly from the rectified mains with minimal external components, making it highly efficient and reliable. The ALTAIR04-900TR is optimized for applications requiring constant output voltage without the need for optocouplers, secondary voltage references, or current sensors, thus simplifying the design and enhancing safety and reliability.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Maximum Switching Frequency | 166 kHz | |
| Power Section Voltage Rating | 900 V | |
| Vcc Operating Range | 11.5 - 23 V | |
| Turn-on Threshold | 2.46 - 2.54 V (at Tj = 25°C) | |
| Operating Temperature Range | -40 to 150°C | |
| Package Type | SOIC-16 | |
| RDS(on) of MOSFET | 16 Ω (typical) |
Key Features
- Optoless Primary Side Constant Voltage Operation: Eliminates the need for optocouplers, secondary voltage references, and current sensors.
- Adjustable and Mains-Independent Maximum Output Current: Ensures safe operation during overload and short-circuit conditions.
- Quasi-Resonant Valley Switching Operation: Minimizes turn-on losses, reduces EMI emissions, and ensures safe behavior in short-circuit conditions.
- Low Standby Consumption: Enters a controlled burst-mode operation at very light loads to minimize standby power.
- Overcurrent Protection: Protects against transformer saturation and secondary diode short-circuit with hiccup-mode operation.
- High Voltage Start-Up Generator: Ensures reliable start-up and maintains the Vcc voltage during operation.
- Zero-Current Detection and Triggering: Detects transformer demagnetization for quasi-resonant operation.
Applications
- Switch-Mode Power Supplies (SMPS) for Energy Metering
- Auxiliary Power Supplies for 3-Phase Input Industrial Systems
- AC-DC Adapters
Q & A
- What is the maximum switching frequency of the ALTAIR04-900TR?
The maximum switching frequency is 166 kHz.
- What is the voltage rating of the power section in the ALTAIR04-900TR?
The power section is rated for 900 V.
- What is the operating voltage range for Vcc in the ALTAIR04-900TR?
The Vcc operating range is from 11.5 V to 23 V.
- How does the ALTAIR04-900TR handle overcurrent protection?
The device features hiccup-mode operation to protect against short-circuit conditions and transformer saturation.
- What is the purpose of the high voltage start-up generator in the ALTAIR04-900TR?
The high voltage start-up generator ensures reliable start-up and maintains the Vcc voltage during operation.
- How does the ALTAIR04-900TR reduce standby power consumption?
The device enters a controlled burst-mode operation at very light loads to minimize standby power consumption.
- What are the key benefits of quasi-resonant valley switching operation in the ALTAIR04-900TR?
The benefits include minimized turn-on losses, reduced EMI emissions, and safe behavior in short-circuit conditions.
- What types of applications is the ALTAIR04-900TR suitable for?
The device is suitable for SMPS for energy metering, auxiliary power supplies for 3-phase input industrial systems, and AC-DC adapters.
- How does the ALTAIR04-900TR ensure accurate output voltage regulation?
The device uses primary-sensing feedback and a voltage partition of the auxiliary winding to ensure accurate output voltage regulation.
- What is the significance of the zero-current detection and triggering block in the ALTAIR04-900TR?
The zero-current detection and triggering block detects transformer demagnetization for quasi-resonant operation, ensuring synchronized MOSFET turn-on.
