Hi, Team
My customer use our UCC28065 in their PFC power module, they prefer Dynamic adjust the R_TSET for UCC28065, the detail is as below:
As we know, the R_TSET value is control the Ton time( or max ton time) of the UCC28065. the Max_Ton_time limit the max output power.
that means we can change the R_TSET for different output power requirement.
So customer prefer to adjust the R_TSET value for different output power.
For example, if Vin_ac is high, increase the output power by increasing the Ton time. and if Vin_ac is low, decrease the output power by lower the Ton time. So they prefer use R_TSET value for different Vin_AC to control the Ton.
Base on their requirement, we suggested them using MCU GPIO pin to set deference R_TSET. (GPIO control a Mosfet On/off, and the Mosfet control the R_TSET), just like below:
For our suggestions, customer think it’s OK. But they feedback that add 1 more Mosfet can only add one R_TSET step.
They prefer add more steps base on their system’s requirement. They prefer TI to check whether they can use MCU PWM to get more step, see as below: (PWM signal output from MCU, and use RC filter to get a DC value to TSET pin.
1, Could u help to check whether we can use PWM+ RC filter to adjust the Ton time?
2, if not, Do u have any others suggestions base on customer’s requirement?
Thanks.
GW
