1 Answer
Secondary-side feedback is a technique used in power supplies, especially in switch-mode power supplies (SMPS), to control and regulate the output voltage or current.
In a typical power supply, feedback is used to ensure that the output voltage stays stable despite variations in input voltage, load, or temperature. This feedback can be taken either from the primary side (before the transformer) or the secondary side (after the transformer, where the output is).
**Secondary-side feedback** refers to measuring the output voltage or current on the secondary side of the transformer and using that information to adjust the control circuitry. This feedback loop helps to regulate the output more accurately.
### How it works:
1. **Output measurement**: The voltage or current is sensed on the secondary side of the transformer (after the rectifier and filter).
2. **Feedback signal**: This sensed signal is sent back to the control loop, often through an optocoupler or another isolating component to keep the primary and secondary circuits electrically separate.
3. **Regulation**: The feedback signal is compared with a reference value (set by the designer) to adjust the switching behavior of the power supply, ensuring that the output remains at the desired level.
This method is beneficial because it offers more accurate regulation and reduces the effects of transformer losses or variations in the primary-side control loop. It is commonly used in isolated designs, where the primary and secondary sides are electrically isolated, such as in flyback, buck, and boost converters.
In a typical power supply, feedback is used to ensure that the output voltage stays stable despite variations in input voltage, load, or temperature. This feedback can be taken either from the primary side (before the transformer) or the secondary side (after the transformer, where the output is).
**Secondary-side feedback** refers to measuring the output voltage or current on the secondary side of the transformer and using that information to adjust the control circuitry. This feedback loop helps to regulate the output more accurately.
### How it works:
1. **Output measurement**: The voltage or current is sensed on the secondary side of the transformer (after the rectifier and filter).
2. **Feedback signal**: This sensed signal is sent back to the control loop, often through an optocoupler or another isolating component to keep the primary and secondary circuits electrically separate.
3. **Regulation**: The feedback signal is compared with a reference value (set by the designer) to adjust the switching behavior of the power supply, ensuring that the output remains at the desired level.
This method is beneficial because it offers more accurate regulation and reduces the effects of transformer losses or variations in the primary-side control loop. It is commonly used in isolated designs, where the primary and secondary sides are electrically isolated, such as in flyback, buck, and boost converters.