Overview
Before introducing differential Hall current sensors, first explain what a differential Hall sensor is.
A differential Hall sensor is based on the Hall effect and measures the intensity and direction of a magnetic field. Its principle uses the Hall effect: when current flows through a conductor placed in a magnetic field, a voltage difference appears across the conductor. A differential Hall sensor uses two Hall elements and measures the voltage difference between them to determine the magnetic field magnitude and direction.
Operating principle
When a magnetic field acts on the sensor, the voltage difference between the two Hall elements changes. The magnitude of this change depends on the magnetic field strength and direction. By measuring this voltage difference, the magnetic field vector can be inferred.
Advantages and applications
Differential Hall sensors offer high accuracy, fast response, good stability, and strong immunity to interference. Typical applications include magnetic field measurement, motor control, magnetometers, geomagnetic measurement, and navigation.
CH706 / CH706W: Isolated Differential Hall Current Sensor
The CH706/CH706W from Yire Semiconductor is an isolated differential Hall current sensor designed to resist common-mode magnetic interference.
Primary applications
- Motor control
- Load detection and management
- Switch-mode power supplies
- Solar inverters
- Public-address speaker current detection
Product description
The CH706(W) is a factory-programmable, low-noise, high-precision linear Hall-effect sensor IC with a bandwidth of 120 kHz. The device consists of a precision, low-offset, linear Hall sensor circuit with a copper conduction path located near the chip surface. An external current flowing through this copper path generates a magnetic field that is sensed by the integrated Hall element and converted to a proportional voltage. The typical resistance of the conduction path is 0.8 mΩ. The conduction-path terminals are electrically isolated from the sensor pins, enabling use in high-side current-sensing applications without requiring high-end differential amplifiers or other costly isolation techniques.
These Hall-effect sensors provide a voltage output proportional to the applied magnetic field. The quiescent output voltage can be programmed by the user in six options: approximately 50% of the supply, 10% of the supply, or set to fixed values.
The CH706(W) current sensor offers a cost-effective and accurate solution for detecting AC or DC current in industrial, commercial, and communication systems. Its small package suits space-constrained applications and reduces printed circuit board area. Typical applications include motor control, load detection and management, switch-mode power supplies, and solar inverters.
Programmability via the VREF pin improves device accuracy for end-of-line optimization without the complexity and cost of fully programmable devices. The device uses EEPROM to optimize device sensitivity and quiescent output voltage (QVO) for a given application or circuit. It also allows programming of the temperature coefficients of sensitivity and QVO during end-of-line testing to optimize performance across the temperature range.
User-selectable output voltage clamping, open-wire detection, and programmable features allow the CH706(W) to meet manufacturing tolerances and achieve high reliability across a wide temperature range from -40°C to 125°C for automotive-grade applications.
The CH706(W) provides an additional VREF output that functions as an I/O pin. Typically, the output voltage equals the quiescent output measured with zero magnetic field. This pin can also accept a signal from an external reference voltage.
