Tool/software:
Hi,
I plan to use drv8835 to drive magnetic latching relays.
I have some questions:
Can one channel of DRV8835 (max current 1.5A) drive 16 relays like G6KU-2F-Y-TR-5VDC (current 21.1mA)?
Does the circuit need additional protection diodes?
What should I pay attention to in circuit design?
Thank you!
Hi Applo,
You are correct. Each H-bridge is designed to support up to 1.5 A. So 16x relays with 21.1 mA each would work out to 337.6 mA and can be supported by one H-bridge. I assume 5 V supply voltage for motor operating supply voltage will be used.
Latching relays would need polarity reversal for latch and unlatch operation hence driven by H-bridge. No additional protection diodes would be needed.
"What should I pay attention to in circuit design?". General electrical layout best practices will be good. I assume you'd connect 16x relays in parallel, yes? You could connect all of them to a star point for each output in your layout. This would prevent any cross talk or other interferences. While using the bridge control logic always use Forward, Reverse and Brake control for relay operation. Do not use Coast (if IN/IN PWM mode is used) as this would make the H-bridge hi-Z and allow kickback voltage across the relay to rise when the relay coil is de-energized.
Thank you.
Regards, Murugavel
