Patent ID: 8400185

Claim:
A driving circuit with zero current shutdown, the driving circuit comprising: a) a linear regulating circuit configured to receive an input voltage source, and to output an output voltage at a first output terminal; b) a start-up circuit having a threshold voltage, said start-up circuit being configured to receive an external enable signal; c) a first power switch configured to receive both said output voltage of said linear regulating circuit and said external enable signal, and to generate an internal enable signal at a second output terminal, said internal enable signal being configured to drive a logic circuit; d) wherein when said external enable signal is lower than said threshold voltage, said driving circuit is disabled; e) wherein when said external enable signal is higher than said threshold voltage, said start-up circuit is configured to output a first current; f) wherein said output voltage at said first output terminal is generated by said linear regulating circuit in accordance with said first current; g) a first current mirror coupled to said input voltage source, said linear regulating circuit, and said start-up circuit, wherein said first current mirror is configured to mirror said first current to generate a first mirror current when said external enable signal is higher than said threshold voltage, and wherein said first mirror current is configured to be used as a bias current by said linear regulating circuit; and h) a feedback circuit coupled to said start-up circuit and said first current mirror, wherein said first current is configured to be received by said feedback circuit to generate a second current with a constant value.