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USB EZ-PD Type-C

New Contributor II

I developed a power adapter using cypd3174, and use the source code in EZ-PD CCGx Power SDK(CYPD3174-24LQXQ_pa_opto_fb), and I compile and flashing the firmware  into power adapter, everything seems ok. however, the problem is that if the target devices can't support USB PD, then I need to provide a default voltage for it, where can set it in "CYPD3174-24LQXQ_pa_opto_fb" source code.

And I looked for document, guess the "psrc_set_voltage" API can do this, but I could't find where to add.

thx.   

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Moderator
Moderator

Hi,

CYPD3174-24LQXQ_pa_opto_fb is Opto Feedback design, which is means the feedback from the secondary side to the primary fly-back controller is through an opto isolator. Default 5 V VBUS is dictated by the reference voltage Vref and the internal resistor divider of 200 k and 68 k.

If you are designing a Type-C design, strongly recommend you are not change 5V default value.

If you insist to, you can refer below SPEC,

The CV loop IDACs can sink up to 102.3 μA of current and can source up to 12.7 μA of current.

And then, you can try to change the value of IDAC by below API.

void pd_hal_set_fb_dac(int16_t dac_value)

Best Regards,

Lisa

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3 Replies
Moderator
Moderator

Hi ,

CCG3PA firmware support your requirements by default. If you attached a Type-C device without PD, the 5V will be enabled on the VBUS.

Best Regards,

Lisa

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New Contributor II

Hi Lisa,

     If I want to change the default valtage and where/how to do this?

thank you very much.

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Moderator
Moderator

Hi,

CYPD3174-24LQXQ_pa_opto_fb is Opto Feedback design, which is means the feedback from the secondary side to the primary fly-back controller is through an opto isolator. Default 5 V VBUS is dictated by the reference voltage Vref and the internal resistor divider of 200 k and 68 k.

If you are designing a Type-C design, strongly recommend you are not change 5V default value.

If you insist to, you can refer below SPEC,

The CV loop IDACs can sink up to 102.3 μA of current and can source up to 12.7 μA of current.

And then, you can try to change the value of IDAC by below API.

void pd_hal_set_fb_dac(int16_t dac_value)

Best Regards,

Lisa

View solution in original post