I’m using MP8008 or MP8009 to make a 24V output with POE51Q-24 transformer.
Is TL431 voltage divider the only thing that needs to be designed differently from the EVM circuit?
Can I use the POE51Q-24 transformer for circuit design of MP8008 and MP8009?
I designed d2 as 12v, and the auxiliary winding outputs 12v.
By the way, do you know why burnd d2 when connect d11?
Is there a reason why d2 is 9.1v?
I look forward to your prompt reply.
Looks like it, the only ratio in the transformer that has changed is the secondary winding. Looks which is double the 12V version. So the reflected flyback voltage will be the same as the 12V version and the tertiary voltage will be the same as the 12V version. Voltage ratings of output caps do need to be observed
The data sheet states that the secondary winding - 24 volts, while the auxiliary produces 12 volts.
also Is there a reason why d2 is 9.1v?
I designed d2 as 12v, and the auxiliary winding outputs 12v.
By the way, do you know why burnd d2 when connect d11?
I look forward to your prompt reply.
D2 should be OK unless the transistor was removed and it is now directly across the Vin so that a 12V winding is being loaded with a 9V zener. Bearing in mind that you are receiving support from some internet weirdo, here is what I think are the issues around the choice of D2
D2 is intended to provide about 8.5V from the high voltage pass transistor to allow the flyback to start up. The flyback looks like it can operate down to a Vin of 5V or so and up to a Vin of 40 ( nice range) Operating the flyback from the high side via a linear regulator is inefficient, so what they have done is put 12V or so from the flyback winding on the emitter of the high voltage pass transistor. This will turn it off as the base emitter junction will be back biased by 3V and the flyback will operate from power sourced from the tertiary winding at 90% efficiency rather than sourced from a HV liner regulator at 20% efficiency.
So D2 value is quite flexible, it has to be a few volts lower than the tertiary winding voltage in order for the tertiary winding to take over powering the flyback, other than that D2 exact value can be 7 to 30V assuming the tertiary is slightly higher. The circuit looks like it is optimized for a tertiary of 12V however. 9.1V seems like a fine choice 10 would be OK too I suspect
