Voltage doubler with capacitor module for increasing capacitance

Patent metadata

Field	Value
Publication number	US-10033269-B2
Application number	US-201615142059-A
Country	US
Kind code	B2
Filing date	Apr 29, 2016
Priority date	Apr 29, 2016
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

Abstract

In one example, a circuit includes an alternating current (AC) voltage source, a voltage rail, a reference rail, a first capacitor, a second capacitor, and a switching unit. The AC voltage source is configured to supply voltage in a first direction during a first half of a cycle and supply voltage in a second direction during a second half of the cycle. During a first state of the circuit, the voltage in the first direction supplied by the AC voltage source charges the first capacitor and the voltage in the second direction supplied by the AC voltage source charges the first capacitor. During a second state of the circuit, the voltage in the first direction supplied by the AC voltage source charges the first capacitor and the voltage in the second direction supplied by the AC voltage source charges the second capacitor.

First claim

The invention claimed is:

1. A circuit comprising:
an alternating current (AC) voltage source including a first node and a second node;
a voltage rail;
a reference rail;
a first capacitor including a first node and a second node, the first node of the first capacitor being coupled to the voltage rail;
a second capacitor including a first node coupled to the second node of the first capacitor and a second node coupled to the reference rail;
a rectifier configured to receive an AC voltage from the AC voltage source and output a rectified voltage, wherein the rectifier comprises:
a first diode including an anode coupled to the reference rail and a cathode coupled to the second node of the AC voltage source;
a second diode including an anode coupled to the second node of the AC voltage source and a cathode coupled to the voltage rail; and
a third diode including an anode coupled to the first node of the AC voltage source and a cathode coupled to the voltage rail;

a switching unit comprising a switching element, the switching unit being configured to receive the rectified voltage and selectively connect, with the switching element, the first capacitor and the second capacitor such that a peak voltage of a series string comprising the first capacitor and the second capacitor is greater than a peak voltage of the AC voltage, wherein the switching element includes a first node coupled to the anode of the third diode, a second node coupled to the second node of the first capacitor and the first node of the second capacitor, and a control node; and
a capacitor module configured to selectively increase a capacitance between the voltage rail and the reference rail in response to determining that the rectified voltage does not exceed a voltage threshold.

2. The circuit according to claim 1 , wherein the switching element comprises:
a first voltage controlled circuit element.

3. The circuit according to claim 2 , wherein the switching unit further comprises:
a second voltage controlled circuit element including a first node coupled to the second node of the first capacitor, a second node coupled to the reference rail, and a control node.

4. The circuit according to claim 1 , wherein the capacitor module comprises:
a third capacitor; and
a second switching unit configured to operate in a closed state and an open state,
wherein the second switching unit couples the third capacitor in parallel with a series string comprising the first capacitor and the second capacitor in the closed state, and
wherein the second switching unit decouples the third capacitor from the series string comprising the first capacitor and the second capacitor in the open state.

5. The circuit according to claim 1 , wherein the capacitor module comprises:
a third capacitor; and
a second switching unit configured to operate in a closed state and an open state,
wherein the second switching unit couples the third capacitor in parallel with the first capacitor in the closed state, and
wherein the second switching unit decouples the third capacitor from the first capacitor in the open state.

6. A system comprising:
an alternating current (AC) voltage source including a first node and a second node;
an adapter comprising:
a rectifier configured to receive an AC voltage from the AC voltage source and supply a rectified voltage to a voltage rail and a reference rail, wherein the rectifier comprises:
a first diode including an anode coupled to the reference rail and a cathode coupled to the second node of the AC voltage source;
a second diode including an anode coupled to the second node of the AC voltage source and a cathode coupled to the voltage rail; and
a third diode including an anode coupled to the first node of the AC voltage source and a cathode coupled to the voltage rail;

a series string comprising a first capacitor and second capacitor, the series string being coupled to the voltage rail and to the reference rail;
a switching unit comprising a switching element, the switching unit being configured to selectively connect, with the switching element, the first capacitor and the second capacitor such that a peak voltage of the series string comprising the first capacitor and the second capacitor is greater than a peak voltage of the AC voltage from the AC voltage source, wherein the switching element includes a first node coupled to the anode of the third diode, a second node coupled to the first capacitor and the second capacitor, and a control node;
a capacitor module configured to reduce an AC voltage ripple of the series string comprising the first capacitor and the second capacitor; and
a converter configured to receive the voltage of the series string comprising the first capacitor and the second capacitor and output a direct current (DC) voltage; and

a load configured to receive the DC voltage from the converter.

7. The system according to claim 6 , wherein the converter comprises:
a switched-mode power converter configured to receive the rectified AC voltage at a first voltage and output a DC voltage at a second voltage.

8. The system according to claim 7 , wherein the switched-mode power converter is configured to provide galvanic isolation between the AC voltage source and the load.

9. The system according to claim 8 , wherein:
the load is an electronic device configured to operate at the second voltage.

10. The system according to claim 6 , wherein the capacitor module comprises:
a third capacitor; and
a switching unit configured to operate in a closed state and an open state,
wherein the switching unit couples the third capacitor in parallel with the series string in the closed state, and
wherein the switching unit decouples the third capacitor from the series string in the open state.

11. The system according to claim 6 , wherein the capacitor module comprises:
a third capacitor; and
a switching unit configured to operate in a closed state and an open state,
wherein the switching unit couples the third capacitor in parallel with the first capacitor in the closed state, and
wherein the switching unit decouples the third capacitor from the first capacitor in the open state.

12. The system according to claim 6 , wherein:
the AC voltage source is configured to supply voltage in a first direction during a first half of a cycle and supply voltage in a second direction during a second half of the cycle, the first direction being opposite from the second direction;
the switching unit is further configured to operate the system in a first state and a second state;
during the first state of the system, the voltage in the first direction supplied by the AC voltage source charges the first capacitor and the voltage in the second direction supplied by the AC voltage source charges the first capacitor; and
during the second state of the system, the voltage in the first direction supplied by the AC voltage source charges the first capacitor and the voltage in the second direction supplied by the AC voltage source charges the second capacitor.

Assignees

• Infineon Technologies Austria Ag

Inventors

• Leong Kennith Kin
• Lind Anders

Classifications

• H02M7/06

  using discharge tubes without control electrode or semiconductor devices without control electrode · CPC title

• H02M3/07 Primary

  using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps} · CPC title

• H02M7/155

  using semiconductor devices only · CPC title

• H02M1/10 Primary

  Arrangements incorporating converting means for enabling loads to be operated at will from different kinds of power supplies, e.g. from AC or DC · CPC title

• H02J7/345

  using capacitors as storage or buffering devices · CPC title