DC/DC voltage multiplier with selective charge/discharge

• US 5,095,223 A
• Filed: 05/21/1991
• Issued: 03/10/1992
• Est. Priority Date: 06/13/1990
• Status: Expired due to Fees

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Thomas, Alexander C.
• Primary Examiner(s): STERRETT, JEFFREY L
• Application Number:
  US07/703,512
• Time in Patent Office: 294 Days
• Field of Search: 363/59, 363/60, 320/1, 307/110
• US Class Current: 307/110
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps

Abstract

A DC/DC voltage multiplier comprises a charging source (Vs) connected between first and second terminals (Vdd and Vss), a storage capacitor (Ctr) connected between the first terminal and a third terminal (Vdd and Vtr), a plurality of voltage pump stages each comprising four switches (S1a, S1b and S1c) and a pump capacitor (C1). The switches are actuated under the control of a clock (not shown) so that the pump capacitors of the stages are charged one at a time. The multiplied voltage output between the first and third terminals Vdd and Vtr of the circuit is provided by the charging source (Vs) and the pump capacitors in those stages not currently being charged (C2,C3). Any number of voltage pump stages can be used provided that the output of each stage is connected to the input of the following stage and the circuit is driven by an appropriate clock. The output of the final stage is connected to the input of the first stage so as to form a ring of pump stages.

Claims

1. A DC/DC voltage multiplier comprising a charging source, a pair of output terminals, a plurality of charge storage devices and connecting means for connecting the charge storage devices in a series chain between the output terminals, the connecting means being operable to rearrange the positions of the charge storage devices in the series chain relative to the output terminals and for connecting the charging source across a different one of said plurality of charge storage devices in each of the successive rearrangements of the charge storage devices.

2. A multiplier as claimed in claim 1, characterized in that a filter is included at one or both of the output terminals.

3. A multiplier as claimed in claim 2, characterized in that said filter comprises a storage capacitor connected between the pair of output terminals.

4. A multiplier as claimed in claim 1 characterized in that the connecting means comprise switching devices.

5. A multiplier as claimed in claim 4, characterized in that the switching devices comprise MOS devices.

6. A multiplier as claimed in claim 1, characterized in that said connecting means are operable to alter the relative positions of the charge storage devices in the series connected chain substantially simultaneously with the connection of the charging source to one of the charge storage devices.

7. A multiplier as claimed in claim 6, characterized in that a filter is included at one or both of the output terminals.

8. A multiplier as claimed in claim 6, characterized in that the connecting means comprise switching devices.

9. A multiplier as claimed in claim 8, characterized in that a filter is included at one or both of the output terminals.

10. A multiplier as claimed in claim 6, characterized in that said connecting means are operable to alter the relative positions of the charge storage devices in order to maintain one of the output terminals at the same potential as one of the terminals of the charging source.

11. A multiplier as claimed in claim 10, characterized in that the connecting means comprise switching devices.

12. A multiplier as claimed in claim 10, characterized in that a filter is included at one or both of the output terminals.

13. A multiplier as claimed in claim 12, characterized in that the connecting means comprise switching devices.

14. A DC/DC voltage multiplier comprising:

a charging source, first and second output terminals and a plurality of charge pump stages arranged in a ring, each charge pump stage having a charge storage device connectable to the charging source, characterized in that each stage comprises a first switch having one terminal connected to a first terminal of the charging source and to the first output terminal, a second terminal of the first switch being connected to one terminal of a second switch and to a first terminal of a charge storage device, a second terminal of the second switch being connected to a first terminal of a third switch and to an output of a preceding stage in the ring, a second terminal of the third switch being connected to the second output terminal, a second terminal of the charge storage device being connected to a first terminal of a fourth switch and to an input to a following stage in the ring and a second terminal of the foruth switch being connected to a second terminal of the charging source, and in that when the first, third and fourth switching means are rendered conductive the second switching means is rendered non-conductive and vice versa, whereby to charge the charge storage device of any one of the charge pump stages the first and the fourth switching means of the stage operate to connect the terminals of the charge storage device to the terminals of the charging source, the third switching means of the stage operates to connect the output from the preceding stage to the second output terminal and the second switching means of the stage operates to disconnect the first terminal of the charge storage device from the output of the preceding stage, the voltage across the first and second output terminals being provided by the series connection of the charging source and the charge storage devices of the other of the charge pump stages.

15. A voltage multiplier comprising:

first and second terminals for connection to a source of input voltage,

first and second output terminals for developing an output voltage which is a multiple of the input voltage,

a plurality of voltage storage stages coupled together in a ring, each stage including a voltage storage device and switching means, and

means for cyclically operating said switching means so as to cyclically couple the voltage storage devices to said first and second terminals in mutually individual time intervals, so as to couple an output of a preceding stage to the second output terminal, and to decouple a first terminal of the voltage storage device from the output of the preceding stage whereby said output voltage is developed across the first and second output terminals at any instant of time by means of a series connection of the input voltage and those voltage storage devices that are then decoupled from the first and second terminals.

16. A voltage multiplier as claimed in claim 15 wherein said voltage storage devices comprise capacitors.

17. A voltage multiplier as claimed in claim 15 wherein said switching means are operated so that as each voltage storage device is coupled to the first and second terminals, the other voltage storage devices in the ring are decoupled from said first and second terminals.