Voltage doubler switched capacitor circuit capable of detecting short circuit of flying capacitor and detection method thereof

Patent metadata

Field	Value
Publication number	US-11870344-B2
Application number	US-202117518747-A
Country	US
Kind code	B2
Filing date	Nov 4, 2021
Priority date	Sep 10, 2021
Publication date	Jan 9, 2024
Grant date	Jan 9, 2024

Abstract

The invention provides a voltage doubler switched capacitor circuit capable of detecting short circuit of flying capacitor and a detection method thereof. The voltage doubler switched capacitor circuit provides a way to connect the flying capacitor in parallel to the charging path, and calculate whether it is charged to a predetermined voltage in the designed charging time interval, and then it can effectively detect whether the flying capacitor is short-circuited.

First claim

What the invention claimed is:

1. A voltage doubler switched capacitor circuit capable of detecting a short circuit of a flying capacitor, comprising:
a main voltage source comprising a positive terminal, and a negative terminal electrically connected to a ground side;
a voltage output terminal comprising a first output terminal, and a second output terminal electrically connected to the ground side;
a first switch having first and second ends thereof connected in series between the positive terminal of the main voltage source and the first output terminal of the voltage output terminal;
a second switch, a third switch, a fourth switch, a fifth switch and the flying capacitor, the second switch and the fourth switch being connected in series between the positive terminal of the main voltage source and the first output terminal of the voltage output terminal, the fifth switch and the flying capacitor being connected in series and then connected in parallel at first and second ends of the second switch, a first end of the third switch being electrically connected between the fifth switch and the flying capacitor, and a second end of the third switch being electrically connected to the ground side;
a stabilizing capacitor having first and second ends thereof respectively connected across the first output terminal and the second output terminal;
a first logic gate that controls on and off of one of the second and third switches and a second logic gate that controls on and off of one of the fourth and fifth switches; and
a detection circuit having first and second ends thereof respectively connected across the first output terminal and the second output terminal, the detection circuit comprising a controller, the controller having an input side thereof electrically connected with first and second comparators, the input side of the controller being for a charging pulse as a signal input, the controller having an output side thereof outputting plural control signals including a first switch control signal, a second switch control signal and a third switch control signal for controlling the first switch, the second and third switches and the fourth and fifth switches.

2. The voltage doubler switched capacitor circuit capable of detecting the short circuit of the flying capacitor as claimed in claim 1 , wherein the first logic gate and the second logic gate each are composed of an OR Gate, the first logic gate having first and second input terminals thereof respectively connected to the first switch control signal and the second switch control signal output by the output side of the controller, the second logic gate having third and fourth input terminals thereof respectively connected to the first switch control signal and the third switch control signal output by the output side of the controller.

3. The voltage doubler switched capacitor circuit capable of detecting the short circuit of the flying capacitor as claimed in claim 1 , wherein each of the first and second comparators comprises a voltage input terminal, and the voltage input terminal of each of the first and second comparators comprises a positive phase input terminal and a negative phase input terminal, the positive phase input terminal of each of the first and second comparators being respectively provided with a voltage divider across the first output terminal and the second output terminal, so that a divided voltage of the voltage output terminal between the voltage dividers of the first and second comparators input into the positive phase input terminal of each of the first and second comparators, the negative phase input terminal of each of the first and second comparators being provided with a first reference voltage and a second reference voltage as an input.

4. The voltage doubler switched capacitor circuit capable of detecting the short circuit of the flying capacitor as claimed in claim 1 , wherein the input side of the controller is electrically connected to a timer, the timer is used to determine whether a charging time of the main voltage source to the stabilizing capacitor is less than a preset time.

5. The voltage doubler switched capacitor circuit capable of detecting the short circuit of the flying capacitor as claimed in claim 1 , wherein a capacitance value of the stabilizing capacitor is greater than that of the flying capacitor, and a capacitance value range of the flying capacitor is 0.5 to 0.05 times that of the stabilizing capacitor.

6. A detection method of a voltage doubler switched capacitor circuit capable of detecting a short circuit of a flying capacitor, comprising the steps of:
A: using a first switch with a larger impedance of the voltage doubler switched capacitor circuit for a soft start;
B: turning on the first switch to disconnect a second switch and a third switch, so that a main voltage source charges a stabilizing capacitor;
C: using a timer of a detection circuit to determine whether a charging time of the main voltage source for the stabilizing capacitor is less than a preset time, if yes, going to step D; if not, going to step H;
D: determining whether a divided voltage of a voltage output terminal is greater than a second reference voltage of a second comparator;
E: turning on the second switch and turning off the third switch, so that the main voltage source charges the flying capacitor, and the flying capacitor stores a voltage difference as a voltage of the main voltage source;
F: turning on the second switch and the third switch to let the voltage of the main voltage source of the flying capacitor be discharged to the stabilizing capacitor connected between the voltage output terminals, so that the voltage output terminal is doubled the voltage of the main voltage source;
G: determining whether the divided voltage of one of the voltage output terminals is greater than a first reference voltage of a first comparator, if yes, going to step I; if not, going to step E;
H: turning off a charging pulse and issuing a short-circuit warning;
I: turning off the charging pulse.

7. The detection method of the voltage doubler switched capacitor circuit capable of detecting the short circuit of the flying capacitor as claimed in claim 6 , wherein the voltage doubler switched capacitor circuit in step A comprises:
the main voltage source comprising a positive terminal, and a negative terminal electrically connected to a ground side;
the voltage output terminal comprising a first output terminal, and a second output terminal electrically connected to the ground side;
the first switch having first and second ends thereof connected in series between the positive terminal of the main voltage source and the first output terminal of the voltage output terminal;
a second switch, a third switch, a fourth switch, a fifth switch and the flying capacitor, the second switch and the fourth switch being connected in series between the positive terminal of the main voltage source and the first output terminal of the voltage output terminal, the fifth switch and the flying capacitor being connected in series and then connected in parallel at first and second ends of the second switch, a first end of the third switch being electrically connected between the fifth switch and the flying capacitor, and other end of the third switch being electrically connected to the ground side;
the stabilizing capacitor having first and second ends thereof respectively connected across the first output terminal and the second output terminal;
a first logic gate that controls on and off of one of the second and third switches and a second logic gate that controls on and off of one of the fourth and fifth switches; and
the detection circuit having first and second ends thereof respectively connected across the fir

Assignees

• Egalax_Empia Tech Inc
• Egalax Empia Tech Inc

Inventors

• Lin Po-Chuan
• Lee I-Tsung

Classifications

• H02M3/073 Primary

  Charge pumps of the Schenkel-type · CPC title

• G01R31/52

  Testing for short-circuits, leakage current or ground faults · CPC title

• H02M1/0012

  Control circuits using digital or numerical techniques (in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873) · CPC title

• H02M3/07 Primary

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

• Y02B70/10

  Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes · CPC title