Motor Brake Driver with Current-Sense Amplifier and Advanced Diagnostics

The MAX22215 integrates one 36V half-bridge FET, one 65V low-side NFET (brake-release NFET), and one unidirectional low-offset current-sense amplifier (CSA). It is primarily intended to drive electromechanical motor brakes and solenoids.

The coil current can be controlled both during the energization and demagnetization phases using pulse-width modulation (PWM), resulting in accurate control of excitation, hold, and demagnetization currents, as well as energizing and de-energizing timings.

The MAX22215 integrates a robust 55V demagnetization clamp, which allows fast demagnetization and eliminates the need of external clamp devices such as TVSs. The clamp features a safe demagnetization function that ensures safe operation by preventing the junction temperature from exceeding safety levels (SafeDemag™ function).

The half-bridge FETs and brake-release NFET feature extremely low RDSON (50mΩ, typ). The high efficiency and low power dissipation make the MAX22215 suitable for space-constrained applications in which high-power density on the PCB is a concern. The MAX22215 can drive up to 3A.

The high-accuracy CSA senses the voltage drop across an external sense resistor both during brake-engaged and brake-released operations. The CSA analog output signal can be used for diagnostic purposes or as feedback signal for an external control loop.

The device operation can be controlled either through a 1MHz I2C serial interface or by using CMOS logic input pins. When I2C is used, several device parameters such as the driver output slew rate and CSA gain can be configured. Moreover, the user has access to fault log registers for diagnostic purposes. Up to 16 devices can share the same I2C bus.

The MAX22215 integrates non-dissipative overcurrent protections (OCPs), undervoltage lockout (UVLO), thermal warning and shutdown, and a brake voltage monitor analog output pin (ODM). Other diagnostic functions have been integrated to detect improper load connections and device malfunctioning. A fault indicator pin (nFAULT) is activated every time a fault occurs.

The MAX22215 is available in a compact 5mm x 7mm, 38-pin TQFN package.

APPLICATIONS

* Industrial Motor Brake Release

* Robotics Motor Brake Release

* Solenoid Drive

* One Half-Bridge Driver Operating up to 36V (RON~50mΩ)

* One LS FET Operating up to 65V (RON ~50mΩ)

* Embedded Demagnetization Circuitry

* 55V High-Power Clamp

* Thermal Control Loop for Safe Operations at High-Demagnetization Energy (SafeDemagTM Function)

* 1MHz I2C Serial Interface for Configuration and Diagnostics

* Configurable Half-Bridge Slew-Rate

* Embedded Dead-Time Circuit to Avoid Crossbar Conduction

* 5V Internal Regulator