Overview
The UCC3889NG4 is an off-line power supply controller produced by Unitrode, now part of Texas Instruments. This controller is designed for low power, low voltage, regulated bias supply applications. It features a unique circuit topology that allows for efficient voltage conversion and inherent short circuit protection. The device is capable of regulating output voltages such as 12V or 18V, and can be programmed for other output voltages less than 18V with additional components.
Key Specifications
| Parameter | Min | Max | Units | |
|---|---|---|---|---|
| VCC Zener Voltage | 8.6 | 9.0 | 9.3 | V |
| Startup Current (VOUT = 0) | 150 | 250 | - | µA |
| Operating Current (VOUT = 11V, F = 150kHz) | 1.2 | 2.5 | - | mA |
| Under-Voltage-Lockout Start Threshold (VOUT = 0) | 8.0 | 8.4 | 8.8 | V |
| Minimum Operating Voltage after Start (VOUT = 0) | 6.0 | 6.3 | 6.6 | V |
| Oscillator Amplitude (VCC = 9V) | 3.5 | 3.7 | 3.9 | V |
| Switching Frequency | - | - | 250 kHz | - |
| Input / Supply Voltage - Max | - | - | 9.3 V | - |
| Topology | - | - | Flyback | - |
Key Features
- Efficient Voltage Conversion: The UCC3889NG4 allows for efficient voltage conversion from high input voltages to lower output voltages, such as 12V or 18V, with a switch duty cycle greater than 10%.
- Inherent Short Circuit Protection: The device provides inherent short circuit protection as the output voltage falls to zero, causing the switch off time to approach infinity.
- Programmable Output Voltage: The output voltage can be easily set to 12V or 18V and can be programmed for other output voltages less than 18V with additional components.
- Isolated Version Capability: An isolated version of the topology can be achieved as described in Unitrode Application Note U-149.
- Low Power and Low Voltage Operation: Optimized for low power and low voltage applications, making it suitable for a variety of bias supply needs.
Applications
The UCC3889NG4 is suitable for various off-line power supply applications, including:
- Low Power Bias Supplies: Ideal for low power, low voltage regulated bias supplies.
- AC-DC Converters: Used in AC-DC converters for efficient voltage conversion from AC inputs to DC outputs.
- Isolated Power Supplies: Can be used to create isolated power supplies as described in the application notes.
- General Power Management: Suitable for general power management in electronic devices requiring regulated DC outputs.
Q & A
- What is the primary function of the UCC3889NG4?
The UCC3889NG4 is an off-line power supply controller designed for low power, low voltage, regulated bias supply applications. - What are the typical output voltages for the UCC3889NG4?
The typical output voltages are 12V and 18V, but it can be programmed for other voltages less than 18V. - Does the UCC3889NG4 have inherent short circuit protection?
Yes, it provides inherent short circuit protection as the output voltage falls to zero, causing the switch off time to approach infinity. - What is the maximum input supply voltage for the UCC3889NG4?
The maximum input supply voltage is 9.3V. - What is the switching frequency of the UCC3889NG4?
The switching frequency is approximately 250 kHz. - Can the UCC3889NG4 be used in isolated power supply applications?
Yes, an isolated version of the topology can be achieved as described in Unitrode Application Note U-149. - What is the under-voltage-lockout start threshold for the UCC3889NG4?
The under-voltage-lockout start threshold is between 8.0V and 8.8V. - What is the minimum operating voltage after start for the UCC3889NG4?
The minimum operating voltage after start is between 6.0V and 6.6V. - What is the topology used by the UCC3889NG4?
The topology used is flyback. - Where can I find additional design information for the UCC3889NG4?
Additional design information is available in Unitrode Application Note U-149.
