I'm encountering a design issue with my switch-mode power supply that utilizes the InnoSwitch3-EP (INN3678C). The SMPS powers up and outputs the required V when the input voltage is 133VAC or higher, under full load conditions (drawing 3A), but I'm facing problems when trying to achieve reliable operation within a lower input voltage range of 85VAC to 110VAC at full load.

When I change the input to a lower voltage e.g 100VAC it does not power up. I can hear clicking noises from the SMPS, maybe stuck in auto reset mode ?

Things I have tried.

1. Tried different combination of undervoltage sense resistor, still no result the minimum stayed around 130VAC.
2. Shorted the undervoltage pin to source so it disables it, as per datasheet. The minimum input AC at full load was 150VAC.
3. Measured across C23 on the primary bias and I can see it was flatulating until the input AC reached ~130VAC. Then it was 15V.

The power supply was designed with universal input (85V-240V). Any help on what I should try doing next?

I'm encountering a design issue with my switch-mode power supply that utilizes the InnoSwitch3-EP (INN3678C). The SMPS powers up and outputs the required V when the input voltage is 133VAC or higher, under full load conditions (drawing 3A), but I'm facing problems when trying to achieve reliable operation within a lower input voltage range of 85VAC to 110VAC at full load.

When I change the input to a lower voltage e.g 100VAC it does not power up. I can hear clicking noises from the SMPS, maybe stuck in auto reset mode ?

Things I have tried.

1. Tried different combination of undervoltage sense resistor, still no result the minimum stayed around 130VAC.
2. Shorted the undervoltage pin to source so it disables it, as per datasheet. The minimum input AC at full load was 150VAC.
3. Measured across C23 on the primary bias and I can see it was oscillating until the input AC reached ~130VAC. Then it was 15V.

The power supply was designed with universal input (85V-240V). Any help on what I should try doing next?

I'm encountering a design issue with my switch-mode power supply that utilizes the InnoSwitch3-EP (INN3678C). The SMPS powers up and outputs the required V when the input voltage is 133VAC or higher, under full load conditions (drawing 3A), but I'm facing problems when trying to achieve reliable operation within a lower input voltage range of 85VAC to 110VAC at full load.

When I change the input to a lower voltage e.g 100VAC it does not power up. I can hear clicking noises from the SMPS, maybe stuck in auto reset mode ?

Things I have tried.

1. Tried different combination of undervoltage sense resistor, still no result the minimum stayed around 130VAC.
2. Shorted the undervoltage pin to source so it disables it, as per datasheet. The minimum input AC at full load was 150VAC.
3. Measured across C8 on the primary bias and I can see it was flatulating until the input AC reached ~130VAC. Then it was 15V.

The power supply was designed with universal input (85V-240V). Any help on what I should try doing next?

I'm encountering a design issue with my switch-mode power supply that utilizes the InnoSwitch3-EP (INN3678C). The SMPS powers up and outputs the required V when the input voltage is 133VAC or higher, under full load conditions (drawing 3A), but I'm facing problems when trying to achieve reliable operation within a lower input voltage range of 85VAC to 110VAC at full load.

When I change the input to a lower voltage e.g 100VAC it does not power up. I can hear clicking noises from the SMPS, maybe stuck in auto reset mode ?

Things I have tried.

1. Tried different combination of undervoltage sense resistor, still no result the minimum stayed around 130VAC.
2. Shorted the undervoltage pin to source so it disables it, as per datasheet. The minimum input AC at full load was 150VAC.
3. Measured across C23 on the primary bias and I can see it was flatulating until the input AC reached ~130VAC. Then it was 15V.

The power supply was designed with universal input (85V-240V). Any help on what I should try doing next?