Voltage doubler using a switching regulator and voltage limiter
View Patent ↗A voltage doubler circuit configuration includes a switching regulator having a variable input voltage and a regulated voltage, and a voltage doubler circuit that utilizes the regulated voltage of the switching regulator. The voltage doubler circuit includes an output capacitor that receives an elevated voltage from a voltage doubler capacitor and an electrical clamp that limits the voltage doubler capacitor from exceeding the regulated voltage. The output voltage is twice the regulated voltage minus circuit losses.
1. An apparatus comprising:
a regulator including an input for a variable input voltage and an output of a regulated voltage, the regulator including a switch node that is configured to alternate connection between the input for the variable input voltage and ground;
a circuit that increases voltage, the circuit being coupled to the output of the regulated voltage of the regulator to charge a first capacitor, the circuit being coupled to the switch node, and the circuit including an output capacitor that receives a charge from the first capacitor, the apparatus producing an output voltage across the output capacitor; and
a limit circuit coupled to the switch node and to the regulated voltage of the regulator, the limit circuit coupled to the first capacitor of the circuit;
wherein the limit circuit comprises a resistor and a clamp diode arranged such that the resistor is connected between the switch node and a negative terminal of the first capacitor, and an anode of the clamp diode is connected to the resistor connection at the negative terminal of the first capacitor and a cathode of the clamp diode is connected to the regulated voltage of the regulator; and
wherein the limit circuit limits a voltage across the first capacitor from exceeding the regulated voltage.
2. The apparatus of claim 1 , wherein the first capacitor is configured to be charged from the regulated voltage when the switch node is coupled to ground, and a voltage on the first capacitor is configured to be stepped-up when the switch node is coupled to the input for the variable input voltage.
3. The apparatus of claim 2 , wherein the stepped-up voltage on the first capacitor is configured to be provided to the output capacitor to provide the output voltage.
4. The apparatus of claim 1 , wherein the output voltage is configured to be substantially twice the variable input voltage plus the regulated voltage minus circuit losses.
5. The apparatus of claim 1 , wherein the output voltage remains stable over a range of the variable input voltage.
6. The apparatus of claim 1 , wherein the regulator is a DC to DC converter.
7. The apparatus of claim 1 , wherein the limit circuit is further configured for fast charging of the first capacitor when a bypass component bypasses the resistor when the switch node is coupled to ground.
8. The apparatus of claim 1 , wherein the apparatus is an electronic device comprising a set-top box, gateway, television, or mobile device.
9. The apparatus of claim 1 , wherein the limit circuit comprises a resistor and a clamp diode.