Power supply circuit, backup power supply system, and moving vehicle
View Patent ↗A charge-pump circuit includes: a capacitor; a plurality of switch elements; and a control circuit. A Zener diode has and an anode connected to the control circuit. The control circuit controls ON/OFF states of the plurality of switch elements to allow a first period and a second period to alternate repeatedly. The first period is a period in which a capacitor is connected to a power supply in parallel. The second period is a period in which the power supply and the capacitor are connected in series to cause a current to flow from the power supply and the capacitor to a load. The control circuit makes, within each cycle of a switching period, a proportion of either the first period or the second period smaller in a second state where the Zener diode is electrically conductive than in a first state where the Zener diode is electrically non-conductive.
1 . A power supply circuit, comprising:
a first terminal to which a power supply is connected;
a second terminal to which a load is connected; and
a charge-pump circuit connected between the first terminal and the second terminal and configured to boost an input voltage supplied from the power supply and output a boosted voltage to the load, wherein
the charge-pump circuit includes: a capacitor; a plurality of switch elements; and a control circuit configured to control ON/OFF states of the plurality of switch elements,
the power supply circuit further comprises a Zener diode, the Zener diode having a cathode connected to the first terminal and an anode connected to the control circuit,
the control circuit is configured to control the ON/OFF states of the plurality of switch elements to repeatedly alternate a first period and a second period, the first period including the capacitor being connected to the power supply in parallel to cause a charging current to flow through the capacitor, the second period including the power supply and the capacitor being connected in series to cause a current to flow from the power supply and the capacitor to the load,
the control circuit is configured to make, within each cycle of a switching period including the first period and the second period, a proportion of one of the first period or the second period smaller in a second state where the Zener diode is electrically conductive than in a first state where the Zener diode is electrically non-conductive, and
the control circuit is configured to change, in the second state, proportions of the first period and the second period within each cycle of the switching period according to a current value of a current flowing through the Zener diode.
2 . The power supply circuit of claim 1 , wherein
the control circuit is configured to, when the input voltage exceeds a threshold voltage in the second state, reduce the proportion of one of the first period or the second period to zero within each cycle of the switching period.
3 . The power supply circuit of claim 1 , wherein
the control circuit is configured to, when the input voltage exceeds a threshold voltage in the second state, reduce the proportion of the second period to zero within each cycle of the switching period.
4 . The power supply circuit of claim 1 , further comprising:
a first diode and a second diode which are connected in series between the first terminal and the second terminal, wherein
the plurality of switch elements includes a first switch element and a second switch element which are connected in series between the first terminal and a reference potential,
the capacitor is connected between a first connection node where the first switch element and the second switch element are connected and a second connection node where the first diode and the second diode are connected,
in the first period, the first switch element switches OFF and the second switch element switches ON, and
in the second period, the first switch element switches ON and the second switch element switches OFF.
5 . The power supply circuit of claim 4 , wherein
the control circuit includes a third switch element including an output terminal connected to control terminals of the first switch element and the second switch element,
the third switch element includes ON/OFF states changed according to a voltage value of a voltage applied to a control terminal of the third switch element, and
in the second state, a voltage generated by superposing a drive voltage on top of a bias voltage is applied to the control terminal of the third switch element, the drive voltage changing between high and low levels in a predetermined cycle, the bias voltage changing according to the current value of the current flowing through the Zener diode.
6 . A backup power supply system, comprising:
the power supply circuit of claim 1 ; and
a backup supply switch, wherein
the load is a first load,
the power supply includes an electrical storage device configured to be charged with electricity by a main power supply,
the backup supply switch is connected between the electrical storage device and a second load different from the first load, and
the backup supply switch is configured to switch ON when the main power supply causes a failure.
7 . A backup power supply system, comprising:
the power supply circuit of claim 5 ; and
a backup supply switch, wherein
the load is a first load,
the power supply includes an electrical storage device configured to be charged with electricity by a main power supply,
the backup supply switch is connected between the electrical storage device and a second load different from the first load, and
the backup supply switch is configured to switch ON when the main power supply causes a failure.
8 . A moving vehicle, comprising:
the power supply circuit of claim 1 ; and
a moving vehicle body configured to be equipped with the power supply circuit.
9 . A moving vehicle, comprising:
the power supply circuit of claim 5 ; and
a moving vehicle body configured to be equipped with the power supply circuit.
10 . A power supply circuit, comprising:
a first terminal to which a power supply is connected;
a second terminal to which a load is connected; and
a charge-pump circuit connected between the first terminal and the second terminal and configured to boost an input voltage supplied from the power supply and output a boosted voltage to the load, wherein
the charge-pump circuit includes: a capacitor; a plurality of switch elements; and a control circuit configured to control ON/OFF states of the plurality of switch elements,
the power supply circuit further comprises a Zener diode, the Zener diode having a cathode connected to the first terminal and an anode connected to the control circuit,
the control circuit is configured to control the ON/OFF states of the plurality of switch elements to repeatedly alternate a first period and a second period, the first period including the capacitor being connected to the power supply in parallel to cause a charging current to flow through the capacitor, the second period including the power supply and the capacitor being connected in series to cause a current to flow from the power supply and the capacitor to the load,
the control circuit is configured to make, within each cycle of a switching period including the first period and the second period, a proportion of one of the first period or the second period smaller in a second state where the Zener diode is electrically conductive than in a first state where the Zener diode is electrically non-conductive,
the power supply circuit further comprises a first diode and a second diode which are connected in series between the first terminal and the second terminal,
the plurality of switch elements includes a first switch element and a second switch element which are connected in series between the first terminal and a reference potential,
the capacitor being connected between a first connection node where the first switch element and the second switch element are connected and a second connection node where the first diode and the second diode are connected,
in the first period, the first switch element switches OFF and the second switch element switches ON,
in the second period, the first switch element switches ON and the second switch element switches OFF,
the control circuit includes a third switch element including an output terminal connected to control terminals of the first switch element and the second switch element,
the third switch element includes ON/OFF states changed according to a voltage value of a voltage applied to a control terminal of the third switch element, and
in the second state, a voltage generated by superposing a drive voltage on top of a bias voltage is applied to the control terminal of the third switch element, the drive voltage changing between high and low levels in a predetermined cycle, the bias voltage changing according to a current value of a current flowing through the Zener diode.
11 . The power supply circuit of claim 10 , wherein
the control circuit is configured to, when the input voltage exceeds a threshold voltage in the second state, reduce the proportion of one of the first period or the second period to zero within each cycle of the switching period.
12 . The power supply circuit of claim 10 , wherein
the control circuit is configured to, when the input voltage exceeds a threshold voltage in the second state, reduce the proportion of the second period to zero within each cycle of the switching period.
13 . A backup power supply system, comprising:
the power supply circuit of claim 10 ; and
a backup supply switch, wherein
the load is a first load,
the power supply includes an electrical storage device configured to be charged with electricity by a main power supply,
the backup supply switch is connected between the electrical storage device and a second load different from the first load, and
the backup supply switch is configured to switch ON when the main power supply causes a failure.
14 . A moving vehicle, comprising:
the power supply circuit of claim 10 ; and
a moving vehicle body configured to be equipped with the power supply circuit.