What Is a Half-Bridge Driver?

A half-bridge driver AON6992 controls a half-bridge circuit composed of two MOSFETs (one high-side MOSFET and one low-side MOSFET). By regulating the switching states of these two MOSFETs, the half-bridge driver enables unidirectional or bidirectional current flow, allowing the adjustment of the voltage or current supplied to the load.

The half-bridge driver works by switching the high-side and low-side MOSFETs alternately, generating an alternating voltage signal to control the load. When the high-side MOSFET is on and the low-side MOSFET is off, current flows from the power source to the load. Conversely, when the high-side MOSFET is off and the low-side MOSFET is on, current flows from the load back to the power source.

In terms of circuit design, a half-bridge driver typically includes an input control circuit, a high-side driver, a low-side driver, and protection modules. It controls the MOSFETs' switching based on input signals while preventing issues such as short circuits or overcurrent caused by improper switching operations.

The Structure of Half-Bridge Driver

The structure of a half-bridge driver AON6992 typically consists of the following components:

Input Control Circuit: It receives external control signals, processes them through logic circuits, and transmits them to the high-side and low-side drivers to control the switching state of the MOSFETs.

High-Side Driver: Responsible for driving the high-side MOSFET, turning it on or off during specific time intervals. Since the source of the high-side MOSFET is usually connected to the high-voltage side, a floating driver is required to provide sufficient gate drive voltage.

Low-Side Driver: Responsible for driving the low-side MOSFET, ensuring it is conducted when the high-side MOSFET is off. The operation of the low-side driver is simpler as its source is typically grounded, and no floating drive is necessary.

Protection Circuit Module: This component prevents faults such as short circuits, overcurrent, and overvoltage, protecting both the driver and the MOSFET from potential damage.

Half-Bridge Driver Applications

Half-bridge drivers AON6992 are widely used in various power management and motor control systems. For instance, in DC-DC converters and switching power supplies, half-bridge drivers control the unidirectional or bidirectional flow of current to regulate voltage. For motor drivers, half-bridge drivers control the switching states of two MOSFETs to adjust the speed and direction of the motor. Due to their efficient switching characteristics and low power consumption, half-bridge drivers are extensively applied in electric vehicles, industrial automation equipment, and solar inverters.

Half-Bridge Driver Advantages

Half-bridge drivers offer several advantages. First, they efficiently control unidirectional or bidirectional current flow, resulting in minimal energy loss. Second, since half-bridge drivers only need to control two MOSFETs, the circuit design is relatively simple, and the component count is lower, providing advantages in terms of cost and space utilization. Additionally, their efficient switching characteristics allow half-bridge drivers to maintain low power consumption even when operating at high frequencies.

Full-Bridge Driver vs. Half-Bridge Driver

Full-bridge drivers and half-bridge drivers share some similarities in terms of structure and function. Both are used to control the switching states of MOSFETs to regulate current flow, which in turn controls the voltage or current applied to the load. They are commonly employed in various power management and motor control systems, particularly in DC-DC converters and switching power supplies. Additionally, both types of drivers offer efficient switching characteristics.

However, there are notable differences between the two. Full-bridge drivers consist of four MOSFETs and enable bidirectional current control, making them suitable for more complex applications, such as controlling the forward and reverse rotation of motors. Half-bridge drivers, on the other hand, only include two MOSFETs and are typically used for unidirectional current control. Their circuit design is simpler, making them ideal for applications where lower power consumption and cost are priorities.