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

Patent metadata

Field	Value
Publication number	US-2023077529-A1
Application number	US-202117518747-A
Country	US
Kind code	A1
Filing date	Nov 4, 2021
Priority date	Sep 10, 2021
Publication date	Mar 16, 2023
Grant date	—

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

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

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

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

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

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

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

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

Assignees

• Egalax_Empia Tech Inc

Inventors

• Lin Po-Chuan
• Lee I-Tsung

Classifications

• H02M3/07 Primary

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

• H02M1/36

  Means for starting or stopping converters · CPC title

• H02M1/32

  Means for protecting converters other than automatic disconnection · 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

• 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