Electronic
From discrete to integrated, three choices of motor drive control

From discrete to integrated, three choices of motor drive control

At present, motor control is generally divided into motor driver ICs, gate driver ICs plus MOS/IGBT power devices. Motor driver ICs are developed in the direction of miniaturization, high performance, high power and high voltage, and gate driver ICs are mainly half-bridge, Three-Phase bridge and isolation series. Each of these three parts has many products on the market, but the gameplay in the motor field is nothing more than “discrete”, “intelligent integration” and “power integration” in terms of product portfolio.

Author: Li Ningyuan

At present, motor control is generally divided into motor driver ICs, gate driver ICs plus MOS/IGBT power devices. Motor driver ICs are developed in the direction of miniaturization, high performance, high power and high voltage, and gate driver ICs are mainly half-bridge, three-phase bridge and isolation series. Each of these three parts has many products on the market, but the gameplay in the motor field is nothing more than “discrete”, “intelligent integration” and “power integration” in terms of product portfolio.

Discrete drive control scheme

This “discrete” type of combination means that each device part is discrete, from MCU to gate driver to MOS. This discrete combination is well understood and belongs to the entry-level gameplay. The three combined parts are separated from each other to ensure the flexibility of each part. For example, the power tube can be directly replaced with a new model, and the overall scheme does not require major changes.

From discrete to integrated, three choices of motor drive control

This drive combination solution can provide a highly expandable product portfolio for stepper motors, BDC and three-phase brushless DC motors. The figure above is a discrete implementation of a stepper motor drive. The free terminals of each winding are connected to independent power switches, and current flows in the motor windings in one direction. The diode is used to clamp the voltage across the switch when it is turned off.

The weakness of this gameplay is obvious. Discrete devices cannot achieve high integration and high compactness. This will make the PCB space occupancy very high.

Intelligent integrated drive control scheme

Intelligent integration refers to the integration of the MCU and the gate driver into an integral module. The integrated module cooperates with the power device to complete the drive and control of the motor.

This kind of integration should be the way to save PCB space the most. From ST’s STSPIN32, this high integration saves about 80% of the space, and at the same time reduces the complexity of the circuit a lot.

The disadvantage of this integrated mode is that the choice of MCU is very limited. As far as the STSPIN32 series is concerned, ST also has two low-voltage and one high-voltage options. This integrated mode is generally used for advanced BLDC control.

Power integrated drive control scheme

The last kind of gameplay is to integrate the gate driver with the power tube. This integration method will also greatly save PCB space, although it is not as large as the 80% space saving by MCU + gate drive integration, it is no problem to achieve a 60% saving. Although this kind of integration has no limitation on MCU selection, correspondingly, it is not so flexible in power supply selection. At the same time, the cost of power integration is the highest among these gameplays.

PWD5F60 is a power integrated device that integrates four N-channel power mosfets with a gate driver and a dual half-bridge. From the performance of this device, the integrated power mosfet has an RDS(ON) of 1.38Ω and a drain-source breakdown voltage of 600 V, and the bootstrap diode provides the gate drive of the upper arm. The high integration of this device can effectively drive the load in a small space. Generally, this kind of power integrated device has UVLO protection function in the lower and upper driving parts, which can prevent the power switch from working under low efficiency or dangerous conditions.

Sacrificing the flexibility of power supply equipment selection and the high cost brought by power integration, this kind of gameplay brings extremely leading EMI performance.

Write at the end

These three modes cover the discrete and integrated gameplay from MCU to gate driver to power tube. The advantages of each gameplay are very prominent, and the corresponding disadvantages are also extremely obvious in comparison. How to choose the matching gameplay from the design according to the motor application direction is the best choice for control.

Author: Li Ningyuan

At present, motor control is generally divided into motor driver ICs, gate driver ICs plus MOS/IGBT power devices. Motor driver ICs are developed in the direction of miniaturization, high performance, high power and high voltage, and gate driver ICs are mainly half-bridge, three-phase bridge and isolation series. Each of these three parts has many products on the market, but the gameplay in the motor field is nothing more than “discrete”, “intelligent integration” and “power integration” in terms of product portfolio.

Discrete drive control scheme

This “discrete” type of combination means that each device part is discrete, from MCU to gate driver to MOS. This discrete combination is well understood and belongs to the entry-level gameplay. The three combined parts are separated from each other to ensure the flexibility of each part. For example, the power tube can be directly replaced with a new model, and the overall scheme does not require major changes.

From discrete to integrated, three choices of motor drive control

This drive combination solution can provide a highly expandable product portfolio for stepper motors, BDC and three-phase brushless DC motors. The figure above is a discrete implementation of a stepper motor drive. The free terminals of each winding are connected to independent power switches, and current flows in the motor windings in one direction. The diode is used to clamp the voltage across the switch when it is turned off.

The weakness of this gameplay is obvious. Discrete devices cannot achieve high integration and high compactness. This will make the PCB space occupancy very high.

Intelligent integrated drive control scheme

Intelligent integration refers to the integration of the MCU and the gate driver into an integral module. The integrated module cooperates with the power device to complete the drive and control of the motor.

This kind of integration should be the way to save PCB space the most. From ST’s STSPIN32, this high integration saves about 80% of the space, and at the same time reduces the complexity of the circuit a lot.

The disadvantage of this integrated mode is that the choice of MCU is very limited. As far as the STSPIN32 series is concerned, ST also has two low-voltage and one high-voltage options. This integrated mode is generally used for advanced BLDC control.

Power integrated drive control scheme

The last kind of gameplay is to integrate the gate driver with the power tube. This integration method will also greatly save PCB space, although it is not as large as the 80% space saving by MCU + gate drive integration, it is no problem to achieve a 60% saving. Although this kind of integration has no limitation on MCU selection, correspondingly, it is not so flexible in power supply selection. At the same time, the cost of power integration is the highest among these gameplays.

PWD5F60 is a power integrated device that integrates four N-channel power MOSFETs with a gate driver and a dual half-bridge. From the performance of this device, the integrated power MOSFET has an RDS(ON) of 1.38Ω and a drain-source breakdown voltage of 600 V, and the bootstrap diode provides the gate drive of the upper arm. The high integration of this device can effectively drive the load in a small space. Generally, this kind of power integrated device has UVLO protection function in the lower and upper driving parts, which can prevent the power switch from working under low efficiency or dangerous conditions.

Sacrificing the flexibility of power supply equipment selection and the high cost brought by power integration, this kind of gameplay brings extremely leading EMI performance.

Write at the end

These three modes cover the discrete and integrated gameplay from MCU to gate driver to power tube. The advantages of each gameplay are very prominent, and the corresponding disadvantages are also extremely obvious in comparison. How to choose the matching gameplay from the design according to the motor application direction is the best choice for control.

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