Overview
The MC34067DW, produced by onsemi, is a high-performance bipolar integrated circuit (IC) designed for variable frequency power control in resonant mode applications. This IC is specifically tailored for zero voltage switching (ZVS) quasi-resonant converter (QRC) applications, particularly in off-line and dc-to-dc converter scenarios. It features a variable frequency oscillator, a precise retriggerable one-shot timer, a temperature-compensated reference, a high-gain wide-bandwidth error amplifier, and dual high-current totem pole outputs suitable for driving power MOSFETs. The MC34067DW is available in both dual-in-line and surface mount packages, making it versatile for various design needs.
Key Specifications
| Characteristic | Symbol | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Power Supply Voltage | VCC | - | - | 20 | V |
| Drive Output Current, Source or Sink (Continuous) | IO | 0.3 | - | 1.5 | A |
| Drive Output Current, Source or Sink (Pulsed, 0.5 μs, 25% Duty Cycle) | IO | 0.3 | - | 1.5 | A |
| Reference Output Voltage (IO = 0 mA, TJ = 25°C) | Vref | 5.0 | 5.1 | 5.2 | V |
| Line Regulation (VCC = 10 V to 18 V) | Regline | - | - | 20 | mV |
| Load Regulation (IO = 0 mA to 10 mA) | Regload | - | - | 20 | mV |
| Operating Junction Temperature | TJ | - | - | 150 | °C |
| Operating Ambient Temperature (MC34067) | TA | 0 | - | 70 | °C |
| Storage Temperature | Tstg | -55 | - | 150 | °C |
Key Features
- Zero Voltage Switch Resonant Mode Operation: Optimized for zero voltage switching (ZVS) quasi-resonant converter (QRC) applications.
- Variable Frequency Oscillator: Control range exceeding 1000:1, suitable for high-frequency power control.
- Precision One-Shot Timer: Provides controlled off-time for precise switching control.
- Internally Trimmed Bandgap Reference: Ensures stable and accurate voltage reference.
- High Gain Wide Bandwidth Error Amplifier: Offers high gain and wide bandwidth for accurate feedback control.
- Dual High Current Totem Pole Outputs: Ideal for driving power MOSFETs.
- Protective Features: Includes high-speed fault comparator and latch, programmable soft-start circuitry, input undervoltage lockout with selectable thresholds, and reference undervoltage lockout.
Applications
The MC34067DW is specifically designed for zero voltage switching (ZVS) quasi-resonant converter (QRC) applications, particularly in off-line and dc-to-dc converter scenarios. It is optimized for double-ended push-pull or bridge type converters operating in continuous conduction mode. The IC is suitable for applications requiring high efficiency, lower switching losses, and reduced EMI emission.
Example applications include:
- DC-to-DC converters
- Off-line power supplies
- High-frequency resonant mode power converters
- Zero voltage switch (ZVS) circuits
Q & A
- What is the primary function of the MC34067DW?
The primary function of the MC34067DW is to provide a fixed off-time to the gates of external power MOSFETs at a repetition rate regulated by a feedback control loop in zero voltage switching resonant mode applications.
- What are the key features of the MC34067DW?
The key features include zero voltage switch resonant mode operation, a variable frequency oscillator, a precision one-shot timer, an internally trimmed bandgap reference, a high-gain wide-bandwidth error amplifier, and dual high-current totem pole outputs.
- What are the protective features of the MC34067DW?
The protective features include a high-speed fault comparator and latch, programmable soft-start circuitry, input undervoltage lockout with selectable thresholds, and reference undervoltage lockout.
- What is the operating temperature range for the MC34067DW?
The operating ambient temperature range for the MC34067DW is 0°C to 70°C, and the storage temperature range is -55°C to 150°C.
- What types of packages are available for the MC34067DW?
The MC34067DW is available in both dual-in-line and surface mount packages.
- What is the maximum power supply voltage for the MC34067DW?
The maximum power supply voltage (VCC) for the MC34067DW is 20 V.
- How does the MC34067DW handle fault conditions?
The MC34067DW includes a high-speed fault comparator and latch that quickly disable the system in case of a fault condition. The fault latch can be reset during startup or by momentarily pulling the Enable/UVLO Adjust pin low.
- What is the purpose of the soft-start circuitry in the MC34067DW?
The soft-start circuitry is designed to ensure a controlled startup of the power supply, preventing large inrush currents and ensuring a smooth transition to full operation.
- What are the benefits of using resonant mode control in power supplies?
Resonant mode control offers benefits such as lower switching losses, higher efficiency, lower EMI emission, and smaller component size.
- Can the MC34067DW be used in automotive applications?
Yes, the NCV prefix version of the MC34067 is AEC-Q100 qualified and PPAP capable, making it suitable for automotive and other applications requiring unique site and control change requirements.
