Overview
The MC34262DR2 is an active power factor controller designed by onsemi, specifically intended for use as a preconverter in electronic ballasts and other power factor correction (PFC) applications. This device is part of the MC34262 and MC33262 series, which incorporate advanced features to enhance power factor correction and overall system efficiency.
The MC34262DR2 integrates several key functional blocks, including an error amplifier, an overvoltage comparator, a multiplier, and a current sense comparator. These components work together to ensure that the preconverter load appears resistive to the AC line, thereby improving power factor and reducing harmonic distortion.
Key Specifications
| Characteristic | Symbol | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Multiplier Input Voltage Range | VPin 3 | 0 | - | 2.5 | V |
| Multiplier Compensation Voltage Range | VPin 2 | 0 | - | 3.5 | V |
| Multiplier Gain | K | 0.43 | 0.65 | 0.87 | 1/V |
| Zero Current Detector Input Threshold Voltage | Vth | 1.33 | 1.6 | 1.87 | V |
| Zero Current Detector Hysteresis | VH | 100 | 200 | 300 | mV |
| Current Sense Comparator Input Bias Current | IIB | - | -0.15 | -1.0 | μA |
| Current Sense Comparator Input Offset Voltage | VIO | - | 9.0 | 25 | mV |
| Drive Output Voltage (VCC = 12 V, Low State, ISink = 20 mA) | VOL | - | 0.3 | 0.8 | V |
| Drive Output Voltage (VCC = 12 V, High State, ISource = 20 mA) | VOH | 9.8 | - | 10.3 | V |
| Startup Threshold (VCC Increasing) | Vth(on) | 11.5 | 13 | 14.5 | V |
| Minimum Operating Voltage After Turn-On (VCC Decreasing) | VShutdown | 7.0 | 8.0 | 9.0 | V |
| Power Supply Current (Startup, VCC = 7.0 V) | ICC | - | 0.25 | 0.4 | mA |
| Power Supply Current (Operating, Dynamic, 50 kHz, CL = 1.0 nF) | ICC | - | 6.5 | 12 | mA |
Key Features
- Error Amplifier: A transconductance type amplifier with high output impedance and controlled voltage-to-current gain. It monitors the average output voltage over several line cycles and has a relatively constant transconductance over temperature.
- Overvoltage Comparator: Prevents runaway output voltage by immediately terminating MOSFET switching when the peak output voltage exceeds a set threshold.
- Multiplier: A single quadrant, two-input multiplier that controls the current sense comparator threshold, ensuring the MOSFET on-time tracks the input line voltage, making the preconverter load appear resistive to the AC line.
- Zero Current Detector: Includes input threshold voltage and hysteresis to accurately detect zero current conditions.
- Current Sense Comparator: Features input bias current and offset voltage specifications to ensure accurate current sensing.
- Drive Output: Capable of sourcing and sinking current with specified output voltage levels and rise/fall times.
- UnderVoltage LockOut (UVLO): Ensures the device operates within a safe voltage range, with startup and shutdown thresholds and hysteresis).
Applications
The MC34262DR2 is primarily used in electronic ballasts and other power factor correction (PFC) applications. It is suitable for:
- High-performance power supplies requiring active PFC.
- Electronic ballasts for lighting systems.
- Power conversion systems where high power factor and low harmonic distortion are critical.
- Industrial and commercial power supplies that need to comply with power factor regulations.
Q & A
- What is the primary function of the MC34262DR2?
The MC34262DR2 is an active power factor controller designed to improve power factor in electronic ballasts and other power conversion systems.
- What are the key components of the MC34262DR2?
The device includes an error amplifier, overvoltage comparator, multiplier, current sense comparator, and drive output stage.
- What is the role of the multiplier in the MC34262DR2?
The multiplier controls the current sense comparator threshold, ensuring the MOSFET on-time tracks the input line voltage, making the preconverter load appear resistive to the AC line.
- What is the purpose of the overvoltage comparator?
The overvoltage comparator prevents runaway output voltage by terminating MOSFET switching when the peak output voltage exceeds a set threshold.
- What are the startup and shutdown voltage thresholds for the MC34262DR2?
The startup threshold is between 11.5 V and 14.5 V, and the minimum operating voltage after turn-on is between 7.0 V and 9.0 V.
- How does the error amplifier function in the MC34262DR2?
The error amplifier is a transconductance type that monitors the average output voltage over several line cycles and has a relatively constant transconductance over temperature.
- What is the typical power supply current during startup and operation?
The startup current is typically 0.25 mA to 0.4 mA, and the operating current is typically 6.5 mA to 12 mA at 50 kHz with a 1.0 nF load capacitor.
- What are the output voltage specifications for the drive output stage?
The drive output voltage can sink and source current with specified levels; for example, the low state output voltage is 0.3 V to 0.8 V at ISink = 20 mA.
- What is the role of the zero current detector in the MC34262DR2?
The zero current detector accurately detects zero current conditions with specified input threshold voltage and hysteresis.
- In which applications is the MC34262DR2 commonly used?
The MC34262DR2 is commonly used in electronic ballasts, high-performance power supplies, and industrial/commercial power supplies requiring active PFC.
