Overview
The FL7921R, produced by onsemi, is a highly integrated electronic component that combines a Power Factor Correction (PFC) controller and a Quasi-Resonant PWM controller. This integration allows for a cost-effective design and reduces the number of external components required. The FL7921R is designed to provide regulated DC output voltage and natural power factor correction using a controlled on-time technique. It also features an innovative THD optimizer to improve input current distortion and overall power factor performance, even at light load conditions.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| VDD Section - Continuously Operating Voltage | - | - | 25 | V |
| VDD Turn-On Threshold Voltage | 16.5 | 18.0 | 19.5 | V |
| VDD PWM-Off Threshold Voltage | 9 | 10 | 11 | V |
| VDD Turn-Off Threshold Voltage | 6.5 | 7.5 | 8.5 | V |
| Startup Current (IDD-ST) | - | - | 30 | μA |
| Operating Current (IDD-OP) | - | - | 10 | mA |
| PFC Maximum On-Time (tON-MAX-PFC) | 22 | 25 | 28 | μs |
| PWM Gate Output Rising Time (tR) | - | 80 | 110 | ns |
| PWM Gate Output Falling Time (tF) | - | 40 | 70 | ns |
| Operating Temperature Range | -40 | - | 105 | °C |
Key Features
- Integrated PFC and Flyback Controller
- Critical-Mode PFC Controller
- Zero-Current Detection for PFC Stage
- Quasi-Resonant Operation for PWM Stage
- Internal Minimum tOFF 8 μs for QR PWM Stage
- Internal 10 ms Soft-Start for PWM
- Brownout Protection
- High / Low Line Over-Power Compensation
- Auto Recovery Over-Current Protection
- Auto Recovery Open-Loop Protection
- Auto Recovery Over-Temperature Protection
- Adjustable Over-Temperature with External NTC through the RT Pin
- Auto Recovery VDD Pin and Output Voltage OVP
Applications
The FL7921R is primarily used in medium to high power LED lighting driver applications. Its integrated PFC and quasi-resonant PWM controller make it suitable for designs requiring high power factor correction and efficient power management.
Q & A
- What is the primary function of the FL7921R?
The FL7921R combines a Power Factor Correction (PFC) controller and a Quasi-Resonant PWM controller to provide regulated DC output voltage and natural power factor correction.
- What is the operating voltage range for the VDD section?
The VDD section operates continuously up to 25 V.
- What is the turn-on threshold voltage for VDD?
The turn-on threshold voltage for VDD is between 16.5 V and 19.5 V.
- What is the purpose of the THD optimizer in the FL7921R?
The THD optimizer reduces input current distortion at zero-crossing duration to improve THD performance.
- What types of protection does the FL7921R offer?
The FL7921R offers various protections including over-current, open-loop, over-temperature, VDD pin OVP, output voltage OVP, and brown-in/out protections.
- How does the FL7921R handle over-temperature protection?
The FL7921R provides adjustable over-temperature protection through the RT pin using an external NTC resistor, and it also has internal over-temperature shutdown.
- What is the typical operating current of the FL7921R?
The typical operating current (IDD-OP) is up to 10 mA.
- What is the maximum on-time for the PFC stage?
The maximum on-time for the PFC stage (tON-MAX-PFC) is between 22 μs and 28 μs.
- What is the package type of the FL7921R?
The FL7921R is available in a 16-pin small outline package (SOP).
- What are the typical applications of the FL7921R?
The FL7921R is used in medium to high power LED lighting driver applications.
