DC/DC converter
A DC/DC converter. In the DC/DC converter, a DC/DC conversion circuit provides an output voltage to a storage capacitor upon receiving an enable signal. First and second resistors are connected in series to produce a first voltage according to the output voltage. A Schmitt trigger is coupled to the first voltage to output a first control signal through an inverter when the first voltage is smaller than a second voltage and to output a second control signal through the inverter when the first voltage is higher than a third voltage. An oscillator is turned off upon receiving the first control signal such that the DC/DC conversion circuit stops providing the output voltage, and is turned on and outputs the enable signal upon receiving the second control signal such that the DC/DC conversion circuit provides the output voltage to the storage capacitor.
1 . A DC/DC converter, comprising:
a DC/DC conversion circuit to provide an output voltage to a storage capacitor upon receiving an enable signal;
a detection circuit to produce a first voltage according to the output voltage of the storage capacitor;
a control circuit having a Schmitt trigger, coupled to the detection circuit to output a first control signal when the first voltage is lower than a second voltage and to output a second control signal when the first voltage is higher than a third voltage; and
a switching circuit turning off upon receiving the first control signal such that the DC/DC conversion circuit stops providing the output voltage, and turning on to output the enable signal upon receiving the second control signal such that the DC/DC conversion circuit provides the output voltage to the storage capacitor.
2 . The DC/DC converter as claimed in claim 1 , wherein the detection circuit is a voltage-divided circuit, comprising:
a first resistor having a first end coupled to the DC/DC conversion circuit; and
a second resistor having a first end coupled to a second end of the first resistor, as an output terminal coupled to an output of the Schmitt trigger.
3 . The DC/DC converter as claimed in claim 1 , wherein the control circuit further comprises an inverter having an input coupled to an output of the Schmitt trigger and an output coupled to the switching circuit.
4 . The DC/DC converter as claimed in claim 1 , wherein the second voltage is smaller than the third voltage.
5 . The DC/DC converter as claimed in claim 1 , further comprising an amplifier coupled between the detection circuit and the control circuit to amplify the first voltage.
6 . The DC/DC converter as claimed in claim 1 , wherein the switching circuit is an oscillator.
7 . A display system, comprising a DC/DC converter as claimed in claim 1 , and a display element coupled to the DC/DC converter, wherein the display element is powered by an output voltage from the DC/DC converter.
8 . The display system as in claim 7 , wherein the display element is at least one of liquid crystal display element, plasma display element and cathode ray tube element.
9 . A circuit, comprising:
a DC/DC conversion circuit and a detection circuit coupled thereto;
the DC/DC conversion circuit enabled to output an output voltage upon receiving an enable signal;
the detection circuit producing a first voltage according to the output voltage; and
a switch, including a trigger, coupled to the DC/DC conversion circuit, the switch responsive to the first voltage to send the enable signal.
10 . The circuit of claim 9 , wherein the trigger is a Schmitt trigger.
11 . The circuit of claim 9 , wherein the trigger includes a triggering level, wherein the trigger sends a second control signal to enable the DC/DC conversion circuit when the first voltage is higher than the triggering level.
12 . The circuit of claim 9 , wherein the trigger includes a triggering level, wherein the trigger outputs a first control signal to enable the DC/DC conversion circuit when the first voltage is lower than the triggering level.
13 . The circuit of claim 9 , wherein the switch includes:
an oscillator, coupled between the trigger and the DC/DC conversion circuit, enabled to output the enable signal; and
the trigger, responsive to the first voltage, outputting a first control signal to enable the oscillator and a second control signal to disenable the oscillator.
14 . The circuit of claim 9 , further comprising an amplifier coupled between the detection circuit and the switch.
15 . An electronic device, comprising:
a power consuming device; and
the circuit of claim 9 , coupled to and supplying power to the power consuming device.
16 . The electronic device as in claim 15 , wherein the power consuming device comprises a display system.