Overview
The L6569 is a high-voltage IC driver designed by STMicroelectronics, primarily for use in electronic lamp ballasts, particularly for compact fluorescent lamps (CFLs) and low-voltage halogen lamp transformers. This driver integrates a symmetric half-bridge inverter and is equipped with a built-in oscillator, similar to a CMOS 555 timer, operating between 25 kHz and 150 kHz. The L6569 features two 270mA buffers that drive the inverter MOSFETs in complementary fashion with a built-in dead time to prevent cross conduction. It also includes a high-voltage level shifter and a lateral DMOS transistor to charge the bootstrap capacitor for the upper buffer.
Key Specifications
| Specification | Value |
|---|---|
| Package | 8-DIP (0.300", 7.62mm), SOIC8 |
| Operating Supply Voltage | 10 V |
| Operating Supply Current | 25 mA |
| Output Current (High and Low Side) | 0.275 A |
| Maximum Voltage Rating | 600 V |
| Oscillator Frequency Range | 25 kHz to 150 kHz |
| Under Voltage Lock Out (UVLO) | 9 V with 1 V hysteresis |
| Start-up Current | 150 µA |
| Dead Time | 1.25 µs |
Key Features
The L6569 boasts several key features that make it suitable for its intended applications:
- Integrated Half-Bridge Driver: Drives the inverter MOSFETs in complementary fashion with a built-in dead time to prevent cross conduction.
- High-Voltage Level Shifter: Realized in BCD offline technology to drive the upper MOSFET buffer.
- Internal Oscillator: Similar to a CMOS 555 timer, operating between 25 kHz and 150 kHz.
- Lateral DMOS Transistor: Integrated to charge the bootstrap capacitor for the upper buffer.
- Under Voltage Lock Out (UVLO): With a 9 V threshold and 1 V hysteresis to ensure safe startup.
- Low Start-up Current: Only 150 µA at power-up.
- Flexible Shutdown Options: Can be shutdown by acting on the CF input oscillator pin or the VS supply pin.
Applications
The primary application of the L6569 is in compact fluorescent lamp (CFL) ballasts. Here are some key application areas:
- CFL Ballasts: The L6569 is the core component in CFL ballast designs, enabling preheat, ignition, and normal lamp operation.
- Low-Voltage Halogen Lamp Transformers: Can be used to drive low-voltage halogen lamps.
- High-Power Applications: For applications above 150W, the L6569 can be used in full bridge inverter configurations.
- Power Factor Correction (PFC): Can be integrated with PFC preregulators to improve power factor in lighting applications.
Q & A
- What is the primary application of the L6569?
The primary application of the L6569 is in compact fluorescent lamp (CFL) ballasts.
- What is the operating frequency range of the L6569's oscillator?
The oscillator operates between 25 kHz and 150 kHz.
- What is the maximum voltage rating of the L6569?
The maximum voltage rating is 600 V.
- How does the L6569 handle startup?
The L6569 has two versions with different startup characteristics. One version drives the lower MOSFET ON at power-up until the supply voltage reaches the Under Voltage Lock Out, while the other version holds both MOSFETs OFF until the UVLO is reached.
- What is the purpose of the high-voltage level shifter in the L6569?
The high-voltage level shifter is used to drive the upper MOSFET buffer.
- How can the L6569 be shutdown?
The L6569 can be shutdown by acting on the CF input oscillator pin or the VS supply pin.
- What is the start-up current of the L6569?
The start-up current is 150 µA.
- Can the L6569 be used in high-power applications?
Yes, for applications above 150W, the L6569 can be used in full bridge inverter configurations.
- Does the L6569 support Power Factor Correction (PFC)?
Yes, the L6569 can be integrated with PFC preregulators to improve power factor in lighting applications.
- What is the dead time in the L6569's driver?
The dead time is 1.25 µs.
