Nami
Solar Enthusiast
- Joined
- Jan 13, 2022
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- 180
High side drive (HSD) is to add a controllable switch at the power end of the circuit to drive the load by controlling the switch of this switch. The design of high side driver is more complex than that of low side driver under the same conditions, and nMOSFET is usually used as the power element.
Low side drive (LSD) is a controllable switch added to the ground terminal of the circuit, which is controlled by closing the ground wire. The low side drive is easy to realize and the circuit structure is simple. It is mainly composed of MOS tubes and a few resistors and capacitors, which is suitable for circuit simplification and cost control.
Working principle of high side drive
The working principle of high side drive is to switch at the power supply end of the load. Under normal conditions, when there is no control signal, the switch tube is not conductive, and there is no current flowing through the load, that is, the load is in the power-off state. When the control signal is valid, open the switch tube, the current flows from the positive end of the power supply through the switch tube into the load, and the load enters the energized state, thus generating a response action. NMOSFET is usually used as power component in high side drive. NMOSFET has low on resistance and is suitable for high power drive.
Working principle of low side drive
The working principle of the low side drive is to switch at the ground terminal of the load. Under normal conditions, when there is no control signal, the switch tube is not conductive, and there is no current flowing through the load, that is, the load is in the power-off state. When the control signal is valid, close the ground wire, open the switch tube, the current flows out from the positive end of the power supply through the load, and the load enters the energized state, thus generating a response action. The low side drive is easy to realize and the circuit structure is simple, which is suitable for circuit simplification and cost control.
Difference between high side drive and low side drive
The main difference between high side drive and low side drive is their response to fault conditions. In cars, due to the ubiquitous grounding metal plate, short-circuit ground fault is more likely to occur than short-circuit power supply fault. For the low side drive, the short ground condition means that the load is turned on; For high side drive, short ground fault will not enable the load. For short-circuit power failure, the low side drive will be short circuited to the power supply to protect the load; The load of the high side drive will continue to turn on.
Compared with the low side protection, the high side protection scheme can still realize the communication between the battery pack and the system terminal even after the protection is triggered. Therefore, there is no need to increase the isolated communication, and the system is safer by disconnecting the battery positive terminal after the protection is triggered.
View attachment 249593
Low side drive (LSD) is a controllable switch added to the ground terminal of the circuit, which is controlled by closing the ground wire. The low side drive is easy to realize and the circuit structure is simple. It is mainly composed of MOS tubes and a few resistors and capacitors, which is suitable for circuit simplification and cost control.
Working principle of high side drive
The working principle of high side drive is to switch at the power supply end of the load. Under normal conditions, when there is no control signal, the switch tube is not conductive, and there is no current flowing through the load, that is, the load is in the power-off state. When the control signal is valid, open the switch tube, the current flows from the positive end of the power supply through the switch tube into the load, and the load enters the energized state, thus generating a response action. NMOSFET is usually used as power component in high side drive. NMOSFET has low on resistance and is suitable for high power drive.
Working principle of low side drive
The working principle of the low side drive is to switch at the ground terminal of the load. Under normal conditions, when there is no control signal, the switch tube is not conductive, and there is no current flowing through the load, that is, the load is in the power-off state. When the control signal is valid, close the ground wire, open the switch tube, the current flows out from the positive end of the power supply through the load, and the load enters the energized state, thus generating a response action. The low side drive is easy to realize and the circuit structure is simple, which is suitable for circuit simplification and cost control.
Difference between high side drive and low side drive
The main difference between high side drive and low side drive is their response to fault conditions. In cars, due to the ubiquitous grounding metal plate, short-circuit ground fault is more likely to occur than short-circuit power supply fault. For the low side drive, the short ground condition means that the load is turned on; For high side drive, short ground fault will not enable the load. For short-circuit power failure, the low side drive will be short circuited to the power supply to protect the load; The load of the high side drive will continue to turn on.
Compared with the low side protection, the high side protection scheme can still realize the communication between the battery pack and the system terminal even after the protection is triggered. Therefore, there is no need to increase the isolated communication, and the system is safer by disconnecting the battery positive terminal after the protection is triggered.
View attachment 249593
