Overview
The UCC256302, produced by Texas Instruments, is a fully featured LLC (LLC Resonant) controller designed for offline AC-DC or isolated DC-DC power systems. This device integrates a high-voltage gate driver and is optimized for low standby power consumption. The UCC256302 uses a novel Hybrid Hysteretic Control (HHC) algorithm, which provides excellent line and load transient response and simplifies compensation design. It includes an integrated high-voltage startup function, eliminating the need for an external bias supply, and supports a wide operating frequency range from 35 kHz to 1 MHz. The device is particularly suited for applications requiring high efficiency and low standby power, such as digital TVs, AC-DC adapters, and industrial power supplies.
Key Specifications
| Parameter | Min | Max | Unit | |
|---|---|---|---|---|
| Input Voltage (HV, HB) | -0.3 | 640 | V | |
| Input Voltage (BLK, FB, LL/SS) | -0.3 | 7 | V | |
| VCC Voltage | -0.3 | 30 | V | |
| Operating Frequency | 35 kHz | 1 MHz | ||
| High-Side Gate Driver Current | 0.6 A / 1.2 A | |||
| Standby Power | 75 mW | |||
| Package Type | SOIC (14) | |||
| Body Size | 9.9 mm x 3.9 mm |
Key Features
- Integrated high-voltage startup function, eliminating the need for an external bias supply.
- Hybrid Hysteretic Control (HHC) for best-in-class transient response and simplified compensation design.
- Optimized low power features enabling 75 mW standby power design with PFC on.
- Advanced burst mode with programmable and adaptive burst power levels.
- Fast exit from burst mode and improved capacitive region avoidance scheme.
- Adaptive dead-time and internal high-side gate drivers (0.6-A and 1.2-A capability).
- Robust soft start with no hard switching and comprehensive protection features including over temperature, output over voltage, input over and under voltage, and three levels of over current protections.
- Opto-coupler low power operation to save up to 20 mW in standby mode.
Applications
- Digital TV SMPS
- AC-DC Adapter
- Multi-Functional Printers
- Projectors
- Merchant DC-to-DC
- High Power Battery Charging
- DIN Rail Power Supply
- Multi-Axis Servo
- ATX Power Supply
- Appliances
- LED Lighting Applications
- Industrial AC-DC
Q & A
- What is the primary function of the UCC256302?
The UCC256302 is an LLC resonant controller designed for offline AC-DC or isolated DC-DC power systems, integrating a high-voltage gate driver and optimized for low standby power consumption.
- What is Hybrid Hysteretic Control (HHC) in the UCC256302?
HHC is a control algorithm that provides excellent line and load transient response and simplifies compensation design by making the open-loop transfer function a first-order system.
- How does the UCC256302 achieve low standby power?
The UCC256302 achieves low standby power through optimized low power features, advanced burst mode, and opto-coupler low power operation, enabling a 75 mW standby power design.
- What are the key protection features of the UCC256302?
The device includes over temperature, output over voltage, input over and under voltage protections, gate driver UVLO protection, and three levels of over current protections.
- What is the operating frequency range of the UCC256302?
The operating frequency range is from 35 kHz to 1 MHz.
- What package types are available for the UCC256302?
The UCC256302 is available in a SOIC (14) package.
- How does the adaptive dead-time feature work in the UCC256302?
The adaptive dead-time feature automatically adjusts the dead-time in the gate signals for the outgoing and incoming power switches to provide optimum efficiency and security of operation.
- What are some common applications for the UCC256302?
Common applications include digital TV SMPS, AC-DC adapters, multi-functional printers, projectors, and industrial AC-DC power supplies.
- How does the UCC256302 handle burst mode operation?
The device automatically transitions into light-load burst mode at low output power levels, with programmable and adaptive burst power levels to optimize efficiency.
- What is the significance of the integrated high-voltage startup function in the UCC256302?
The integrated high-voltage startup function eliminates the need for an external bias supply, reducing the BOM count and minimizing solution size.
