Half-Bridge Driver with Inbuilt Oscillator

This is a Half Bridge with Inbuilt Oscillator project that uses the NCP1392B, a self-oscillating high-voltage MOSFET driver, and two IRF540 MOSFETs. This project is specifically designed for applications that employ half-bridge topology.

The operating frequency of the driver can be adjusted from 25 kHz to 100 kHz using a trimmer potentiometer (PR1). Additionally, the project features adjustable brown-out protection, ensuring that the bulk voltage operates within the correct range. An internal 100 ms or 12.6 ms PFC delay timer guarantees that the main downstream converter will be turned on only when the bulk voltage is fully stabilized. The device also provides a fixed dead time, which helps reduce shoot-through current.

This project is configured for low-voltage applications, supporting up to 36V, with a continuous load current of up to 3A when forced air cooling is used. However, with some modifications, the project can be adapted to support high-voltage applications up to 400V DC. These modifications include replacing the DC bus capacitor, MOSFETs, and selecting an appropriate boot capacitor based on the specific frequency and voltage requirements.

The operating frequency of the project can be adjusted within a range of 25 kHz to 100 kHz using the trimmer potentiometer PR1. The chip itself supports frequencies up to 480 kHz, but the actual frequency depends on the values of PR1 and resistor R6. For frequency adjustment, it is recommended to refer to the chip’s datasheet. It is also important to choose the right MOSFET and boot capacitor for higher frequency applications to ensure optimal performance.

BO: Brown−Out function detects low input voltage conditions. Enable Input, when brought above Vref_EN, stops the driver. Operation is then restored (without any delay) when BO pin voltage drops by EN_Hyste below Vref_EN. Brown−Out Detection: The BO input monitors bulk voltage level via resistor divider R2 and R6 and thus assures that the application is working only for wanted bulk voltage band. The BO input sinks current of 18.2 A until the VrefBO threshold is reached.

Single Ended Push Pull Converter

The components Capacitor C6, C8, Diode D3, and D4 are optional and can be utilized by the user to create a single-ended, push-pull converter. Specifically, the combination of transistor Q1, Q2, an external transformer, and capacitors C6 and C8 forms a single-ended, push-pull converter. This converter operates by applying an alternating voltage to the potential-isolating transformer, effectively utilizing both half-cycles of the oscillation for energy transmission.

Features

• Power Supply Gate Driver 12V-15V DC
• Load Power Supply 24V to 36V DC
• Load Current Continues Up to 3A(Max 5A)
• Wide Operating Frequency Range − from 25 kHz to 100 kHz
• Header Connector for Gate Driver Power
• On Board Power LED
• Screw Terminal for Load Power and Output
• On Board Multi-Turn Pot to Adjust The frequency
• 4 x 4MM PCB Mounting Holes
• PCB Dimensions 56.36 x 36.67 mm

Connections

• CN1 Load Power: Pin 1 + Load Power 24V-36V, Pin 2 = GND
• CN2 Gate Driver Power: Pin 1, 2 = +12V to 15V, Pin 3, 4= GND
• CN3 Output: Pin 1 = Optional for Single Ended Push Pull Output 1/2V, Pin 2 = Half-Bridge Output
• D2: Power LED Gate Driver
• PR1: Frequency Adjust

Schematic

Parts List

Connections

Gerber View

Photos

NCP1392B Datasheet