Overview
The UCC3889N, produced by Texas Instruments, is an off-line power supply controller designed for low power, low voltage, regulated bias supply applications. This controller is optimized for use in non-isolated DC output power supplies, particularly those requiring a regulated output voltage from AC inputs ranging from 80 to 265 volts. The UCC3889N features a unique circuit topology that allows for efficient voltage conversion and inherent short circuit protection.
Key Specifications
| Parameter | Min | Typ | Max | Units |
|---|---|---|---|---|
| VCC Zener Voltage | 8.6 | 9.0 | 9.3 | V |
| Startup Current (VOUT = 0) | 150 | 250 | - | µA |
| Operating Current (I(VOUT)) | 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 |
| CT to DRIVE high Propagation Delay (Overdrive = 0.2V) | 100 | 200 | - | ns |
| CT to DRIVE low Propagation Delay (Overdrive = 0.2V) | 50 | 100 | - | ns |
| Driver VOL (I = 20mA, VCC = 9V) | 0.15 | 0.4 | - | V |
| Driver VOH (I = -20mA, VCC = 9V) | 8.5 | 8.8 | - | V |
| Operating Temperature Range | - | - | 0 to 70 | °C |
Key Features
- Unique Circuit Topology: Allows for efficient voltage conversion and inherent short circuit protection.
- Regulated Output Voltage: Can be easily set to 12V or 18V, and programmed for other output voltages less than 18V with additional components.
- Under-Voltage Lockout (UVLO): Ensures the circuit remains off until VCC reaches a specified threshold (8.4V).
- High Efficiency: Achieves overall efficiency of approximately 50% in certain design examples.
- Switching Frequency: Approximately 100kHz at low line input.
- Isolated Version Capability: Can be configured for isolated operation as described in Unitrode Application Note U-149.
Applications
- Low Power Bias Supplies: Ideal for applications requiring regulated low voltage and low power.
- Non-Isolated DC Output Power Supplies: Suitable for converting AC inputs (80-265V) to regulated DC outputs.
- Consumer Electronics: Can be used in various consumer electronic devices requiring efficient and regulated power supplies.
- Industrial Control Systems: Applicable in industrial settings where reliable and efficient power supply control is necessary.
Q & A
- What is the primary function of the UCC3889N?
The UCC3889N is an off-line power supply controller designed for low power, low voltage, regulated bias supply applications.
- What is the operating temperature range of the UCC3889N?
The operating temperature range is 0°C to 70°C.
- How is the output voltage set in the UCC3889N?
The output voltage can be easily set to 12V or 18V, and programmed for other output voltages less than 18V with additional components.
- What is the typical switching frequency of the UCC3889N at low line input?
Approximately 100kHz.
- Does the UCC3889N have inherent short circuit protection?
Yes, the unique circuit topology provides inherent short circuit protection.
- What is the under-voltage lockout (UVLO) threshold for the UCC3889N?
The UVLO threshold is 8.4V.
- Can the UCC3889N be configured for isolated operation?
Yes, it can be configured for isolated operation as described in Unitrode Application Note U-149.
- What is the typical operating current of the UCC3889N?
Typically 2.5mA.
- What is the startup current of the UCC3889N when VOUT is 0?
Typically 250µA.
- What are some common applications of the UCC3889N?
Low power bias supplies, non-isolated DC output power supplies, consumer electronics, and industrial control systems.
