Overview
The UC2879NG4, produced by Texas Instruments, is a phase shift resonant controller designed to control a bridge power stage by phase shifting the switching of one half-bridge with respect to the other. This controller is part of the UC1879, UC2879, and UC3879 family and is particularly useful in applications requiring high efficiency and constant frequency pulse width modulation. The UC2879NG4 is available in a 20-pin PDIP package and is suitable for various power supply topologies, including voltage mode and current mode operations.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Supply Voltage (VC, VIN) | 20 | V |
| Output Current, source or sink, dc | 20 | mA |
| Output Current, source, sink peak for 0.1 µs at max frequency of 300 kHz | 100 | mA |
| Undervoltage Lockout Start Threshold (VUVSEL = VIN) | 9 - 12.5 | V |
| UVLO Hysteresis (VUVSEL = VIN) | 1.15 - 2.15 | V |
| Supply Current (VIN = VUVSEL = 8 V, VC = 18 V) | 150 µA (startup) | µA |
| Oscillator Initial Accuracy (TA = 25°C) | 180 - 220 | kHz |
| Oscillator Voltage Stability (11 V < VIN < 18 V) | 1 - 2 | % |
Key Features
- Programmable Output Turn On Delay; Zero phase shift capability
- Compatible with Voltage Mode or Current Mode topologies in combination with resonant, zero-voltage switching for high efficiency
- Practical operation at switching frequencies up to 300 kHz
- 10-MHz error amplifier and 5-V precision reference
- Pin programmable undervoltage lockout and overcurrent protection
- Low startup current – 150 µA
- Soft start control
- Outputs active low during undervoltage lockout (UVLO)
- CLKSYNC pin for external clock synchronization or synchronization with other UC3879 units
Applications
The UC2879NG4 is suitable for a variety of high-efficiency power supply applications, including:
- Resonant power supplies
- Zero-voltage switching (ZVS) and zero-current switching (ZCS) applications
- Voltage mode and current mode power supplies
- High-frequency DC-DC converters
- Power supplies requiring high efficiency and reliability
Q & A
- What is the primary function of the UC2879NG4?
The UC2879NG4 is a phase shift resonant controller designed to control a bridge power stage by phase shifting the switching of one half-bridge with respect to the other.
- What are the key topologies supported by the UC2879NG4?
The UC2879NG4 supports voltage mode and current mode topologies in combination with resonant, zero-voltage switching for high efficiency.
- What is the maximum switching frequency of the UC2879NG4?
The UC2879NG4 can operate at switching frequencies up to 300 kHz.
- What protective features does the UC2879NG4 include?
The UC2879NG4 includes undervoltage lockout and overcurrent protection.
- How does the soft start feature work in the UC2879NG4?
The soft start feature in the UC2879NG4 is controlled by a capacitor connected to the SS pin, which gradually ramps up the output voltage during startup.
- Can the UC2879NG4 be synchronized with an external clock?
Yes, the UC2879NG4 can be synchronized with an external clock using the CLKSYNC pin.
- What is the typical startup current of the UC2879NG4?
The typical startup current of the UC2879NG4 is 150 µA.
- What is the precision of the error amplifier in the UC2879NG4?
The error amplifier in the UC2879NG4 operates at 10 MHz.
- What are the package options available for the UC2879NG4?
The UC2879NG4 is available in a 20-pin PDIP package.
- Is the UC2879NG4 RoHS compliant?
Yes, the UC2879NG4 is RoHS compliant.
