Trim circuit for power supply controller
View Patent ↗A trim circuit for a power supply controller includes: a control circuit; at least a capacitance type programmable circuit connection; and a switching circuit, under control of the control circuit, the switching circuit selectively coupling the capacitance type programmable circuit connection to anyone of an operation voltage and a programming voltage, for determining a programming state of the capacitance type programmable circuit connection.
1. A trim circuit for a power supply controller, comprising:
a control circuit;
at least a capacitance type programmable circuit connection; and
a switching circuit, under control of the control circuit, the switching circuit selectively coupling the capacitance type programmable circuit connection to any one of an operation voltage and a programming voltage, for determining a programming state of the capacitance type programmable circuit connection, the switching including:
a first switch selectively coupling the capacitance type programmable circuit connection to the programming voltage; and
a second switch selectively coupling the capacitance type programmable circuit connection to the operation voltage;
wherein the control circuit causes the first switch to be in a conduction state opposite to the second switch at all times, and the trim circuit further comprises:
a current source, coupled between the operation voltage and the second switch, for constantly providing a reference current to the capacitance type programmable circuit connection.
2. The trim circuit according to claim 1 , wherein the capacitance type programmable circuit connection includes a capacitance type antifuse.
3. The trim circuit according to claim 1 , wherein the switching circuit includes a third switch, a fourth switch and a fifth switch,
the third switch selectively coupled between an output and a reference voltage;
the fourth switch selectively coupling the capacitance type programmable circuit connection to the operation voltage; and
the fifth switch selectively coupling the capacitance type programmable circuit connection to the programming voltage.
4. The trim circuit according to claim 3 , further comprising a current source, coupled between the operation voltage and the capacitance type programmable circuit connection or coupled between the programming voltage and the capacitance type programmable circuit connection, for providing a reference current to the capacitance type programmable circuit connection.
5. The trim circuit according to claim 3 , wherein the capacitance type programmable circuit connection includes a capacitance type antifuse.