Overview
The L6599AFD, produced by STMicroelectronics, is an improved version of the L6599A, designed as a double-ended controller for series-resonant half-bridge topology. This controller is optimized for high-voltage applications and offers advanced features such as 50% complementary duty cycle, high accuracy oscillator, and variable frequency control. It is particularly suited for applications requiring high efficiency and reliability in harsh environments, including temperatures as low as -50 °C.
Key Specifications
| Parameter | Min. | Typ. | Max. | Unit |
|---|---|---|---|---|
| IC Supply Voltage (Vcc) | 8.85 | - | 16 | V |
| Turn-on Threshold (VccOn) | 10 | 10.7 | 11.4 | V |
| Turn-off Threshold (VccOff) | 7.45 | 8.15 | 8.85 | V |
| Operating Frequency | - | - | Up to 500 kHz | kHz |
| High-side Gate Driver Voltage (VBOOT) | -1 | - | 618 | V |
| Junction Temperature Range | -50 | - | 150 | °C |
| Quiescent Current (Iq) | - | 1.5 | 2 | mA |
| High-side Gate Driver Current (ILKBOOT) | - | - | 5 µA | µA |
Key Features
- 50% duty cycle, variable frequency control of resonant half bridge
- High accuracy oscillator with up to 500 kHz operating frequency
- Two-level overcurrent protection (OCP): frequency-shift and latched shutdown
- Interface with PFC controller for fault conditions and burst mode operation
- Latched disable input for easy implementation of OTP and/or OVP
- Burst mode operation at light load to minimize input consumption
- Non-linear soft-start for monotonic output voltage rise
- 600 V - rail compatible high-side gate driver with integrated bootstrap diode and high dv/dt immunity
- -300/700 mA high-side and low-side gate drivers with UVLO pull-down
- Input for power-ON/OFF sequencing or brownout protection
Applications
- Outdoor LED drivers
- Street lighting
- AC-DC adapters, open frame SMPS
Q & A
- What is the operating frequency range of the L6599AFD?
The L6599AFD operates up to 500 kHz.
- What is the purpose of the high accuracy oscillator in the L6599AFD?
The high accuracy oscillator is used to regulate the output voltage by modulating the operating frequency.
- How does the L6599AFD protect against overcurrent conditions?
The L6599AFD features two-level overcurrent protection: frequency-shift and latched shutdown.
- What is the role of the burst mode operation in the L6599AFD?
The burst mode operation reduces the converter's input consumption to a minimum at light loads.
- How does the L6599AFD handle power sequencing or brownout protection?
The L6599AFD includes an input for power-ON/OFF sequencing or brownout protection, which shuts down the IC if the voltage falls below a certain threshold.
- What is the significance of the integrated bootstrap diode in the L6599AFD?
The integrated bootstrap diode replaces the external fast-recovery bootstrap diode, enhancing the high-side gate driver's performance and reliability.
- What are the typical applications of the L6599AFD?
The L6599AFD is typically used in outdoor LED drivers, street lighting, and AC-DC adapters, open frame SMPS.
- How does the L6599AFD ensure soft-switching and high-frequency operation?
The L6599AFD ensures soft-switching and high-frequency operation through a fixed deadtime inserted between the turn-off of one switch and the turn-on of the other.
- What is the junction temperature operating range of the L6599AFD?
The junction temperature operating range of the L6599AFD is from -50 °C to 150 °C.
- How does the L6599AFD handle startup to prevent uncontrolled inrush current?
The L6599AFD starts with a programmable maximum frequency that progressively decays to the steady-state value, minimizing output voltage overshoots through a non-linear frequency shift.
