Selection of automotive air conditioning controllers and their key components: Zhongke Alpha Hall current sensors AH91X and AH950

Automobile air conditioning system (AC for short) refers to a system that can regulate the air inside the car, which mainly includes refrigeration system, heating system, ventilation system and air purification system.

The air conditioning controller is connected to multiple sensors in the car, and can accurately obtain the in-car environment through these sensors. At the same time, the controller communicates with the air conditioning control panel through CAN, and can obtain the driver's requirements for the environment in real time. Using internal algorithms, the air conditioning compressor and air conditioning PTC, blower, and actuators such as damper motors and valves are controlled through CAN to achieve precise control of the in-car environment. The detailed air conditioning controller block diagram is as follows:

In the above-mentioned car air conditioning control system, the current needs to be detected, which requires engineers to select appropriate current sensors for design. We can divide current detection into several ranges:

0-40A

The AH91X Hall current sensor IC is an economical and accurate solution for AC or DC current sensing in industrial, automotive, commercial and communication systems. The small package is ideal for space-constrained applications while saving costs due to reduced board area. Typical applications include motor control, load detection and management, switching power supplies and overcurrent fault protection.

AH91X Features:

1.1.2mohm primary conductor resistance for low power loss and high surge current withstand capability;

2. The integrated shield virtually eliminates capacitive coupling from the current conductor to the chip, greatly suppressing output noise due to high dv/dt transients;

3. Industry-leading noise performance, greatly improved bandwidth through proprietary amplifier and filter design techniques, and faster response time in control applications;

4. Isolation voltage 1200V;

5. Stability within the working range: 1.6%@25℃～125℃; 2.5%@-40℃～25℃;

6. The static common mode output point is 2.5V or 50% VCC;

7. Strong anti-interference ability, strong resistance to mechanical stress, and magnetic field parameters are not offset by external pressure;

8.RoHS certified: (EU) 2015/863

50-200A

AH950 Features:

1. Fast output step response time: 4μs

2. Single power supply: 4.5-5.5V

3.65kHz signal bandwidth

4. Zero hysteresis

5. Internal conductor resistance: 120uΩ