SLOSE50A April 2020 – June 2021
PRODUCTION DATA
The current through the motor windings is regulated by an adjustable, off-time PWM current-regulation circuit. When the H-bridge is enabled, current rises through the winding at a rate dependent on the DC voltage, inductance of the winding, and the magnitude of the back EMF present. When the current hits the current regulation threshold, the bridge enters a decay mode for a period of time determined by the TOFF pin setting to decrease the current. After the off-time expires, the bridge is re-enabled, starting another PWM cycle. The current is measured by an internal current mirror architecture that removes the needs for an external power sense resistor.
When the voltage on the VREF pin does not exceed 3.3 V, the ITRIP current (ITRIP) can be calculated as ITRIP (A) = VREFx (V) / 0.66 (V/A).
When the VREF voltage exceeds 3.3V, the ITRIP current does not have a linear relation with the VREF voltage. When VREF is tied to DVDD or an external 5 V, the device can deliver maximum 6.4 A peak current. However, the thermal performance of the device must be carefully considered - heat sinks might be required to drive more than 5 A peak current.
TOFF | OFF-TIME tOFF |
---|---|
0 | 7 µs |
1 | 16 µs |
Hi-Z | 24 µs |
330kΩ to GND | 32 µs |