Output signal of channel differential transceiver

baiyujing

Dear Wolfspeed Technicians,

I am a master's student majoring in power electronics. I am studying the evaluation board CGD12HBXMP and its supporting 2-Channel Differential Transceiver CGD12HB00D. In the output signal of CGD12HB00D, the typical value of the high level voltage is 3.4V(as shown in figure1). But in CGD12HBXMP, the minimum value of the input high level voltage is 3.5V(as shown in figure2). How does CGD12HB00D provide the high level to CGD12HBXMP? Is it always working in an overload state? Because I see that the maximum output voltage high level of CGD12HB00D is not given.

Sincere wishes.

TBhatia

Hello, thank you for your message. A member of our technical team is looking into your questions and we will respond shortly. 

AustinC

Hello baiyujing,

The high-level logic input voltage on the CGD12HBXMP datasheet refers to the single-ended inputs (Power Supply Enable, PWM Enable, and Reset) as opposed to the differential inputs.

The differential drivers on the CGD12HB00D are connected to differential receivers on the CGD12HBXMP, both of which follow the RS-422 communication protocol.

If you'd like to understand the differential signaling further, please refer to the transceiver's datasheet here: https://www.ti.com/lit/gpn/SN65C1168E

Best Regards,

Austin C.

baiyujing

Thank you, I would also like to ask, if the lowest single-end high level output by the front-end circuit is 2.5V, and the highest single-end low level is 0.5V. Their differential signal is at least 2V, which meets the differential signal input requirements of the drive board, but the single-end high level is not within the range given by the drive board datasheet. Can this signal drive the driver board CGD12HBXMP?

AustinC

Hi baiyujing,

The single-ended signals are actually simple passthroughs on the CGD12HB00D. So you'll want to ensure that your microcontroller provides at least 3.5 V for the CGD12HBXMP gate driver to trigger a high signal for the single-ended inputs, Power Supply Disable, PWM Enable, and Reset.

Best Regards,

Austin C.