Overview
The UC2875N/81290 is a phase shift resonant controller integrated circuit designed by Unitrode, now part of Texas Instruments. This component is used to control a bridge power stage by phase-shifting the switching of one half-bridge with respect to the other, enabling constant frequency pulse-width modulation combined with resonant, zero-voltage switching for high efficiency performance at high frequencies.
Key Specifications
| Parameter | Value | Units |
|---|---|---|
| Operating Junction Temperature Range | −55°C to 150°C | °C |
| Storage Temperature Range | −65°C to 150°C | °C |
| Supply Current (IIN) Startup | 150 to 600 µA | µA |
| Supply Current (IIN) | 30 to 44 mA | mA |
| Voltage Reference Output | 4.92 to 5.08 V | V |
| Line Regulation Voltage | 1 to 10 mV | mV |
| Load Regulation Voltage | 5 to 20 mV | mV |
| Noise Voltage | 50 µVrms (10 Hz to 10 kHz) | µVrms |
| Short Circuit Current | 60 mA | mA |
Key Features
- Phase shift resonant control for high efficiency at high frequencies
- Low startup current of 150 µA
- Outputs active low during undervoltage lockout (UVLO)
- Soft-start control
- Latched over-current comparator with full cycle restart
- Programmable time delay for dead-time insertion at output stage turn-on
- Accurate 5 V voltage reference capable of delivering up to 60 mA
- Internal short circuit current limitation for VREF
Applications
The UC2875N/81290 is suitable for various high-power applications requiring efficient and reliable power conversion, such as:
- High-frequency power supplies
- Resonant and zero-voltage switching power stages
- Bridge power stages in voltage or current mode operation
- Industrial power systems requiring high efficiency and reliability
Q & A
- What is the operating junction temperature range of the UC2875N/81290?
The operating junction temperature range is −55°C to 150°C.
- What is the typical supply current during startup?
The typical supply current during startup is 150 to 600 µA.
- What is the voltage reference output of the UC2875N/81290?
The voltage reference output is 4.92 to 5.08 V.
- Does the UC2875N/81290 have built-in over-current protection?
Yes, it has a latched over-current comparator with full cycle restart.
- What is the purpose of the soft-start control in the UC2875N/81290?
The soft-start control helps in gradually increasing the output voltage to prevent inrush currents and ensure smooth startup.
- How is the dead-time insertion controlled in the UC2875N/81290?
The dead-time insertion is controlled through a programmable time delay at the turn-on of each output stage.
- What is the maximum short circuit current of the VREF output?
The maximum short circuit current of the VREF output is 60 mA.
- What type of power stages can the UC2875N/81290 control?
The UC2875N/81290 can control bridge power stages in either voltage or current mode operation.
- How should the supply voltages (VIN and VC) be bypassed for proper operation?
The supply voltages should be bypassed directly to the GND and PWRGND pins with low ESR, low ESL capacitors.
- What happens when the VIN exceeds the upper undervoltage lockout threshold?
When VIN exceeds the upper undervoltage lockout threshold, the supply current (IIN) will increase significantly, and the chip will become active.
