Arrangement for driving display units with an adaptive start sequence

• US 6,914,473 B2
• Filed: 02/21/2002
• Issued: 07/05/2005
• Est. Priority Date: 02/23/2001
• Status: Expired due to Fees

• Current Assignee: Entropic Communications Incorporated (Maxlinear Incorporated)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Hohenwarter, Harald
• Primary Examiner(s): Cunningham, Terry D.
• Application Number:
  US10/081,891
• Publication Number:
  US 20020130708A1
• Time in Patent Office: 1,230 Days
• Field of Search: 327/535, 327/536, 327/540, 327/541, 327/543, 327/546, 365227-229
• US Class Current: 327/535
• CPC Class Codes: G09G 2330/02 Details of power systems and of start or stop of display operation
• CPC Class Codes: G09G 2330/026 Arrangements or methods related to booting a display
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps

Abstract

The invention relates to a circuit arrangement which includes a subvoltage generating unit and a voltage multiplier for generating at least one voltage Vmult, it being arranged to control the voltage multiplier by switching the voltage multiplier to a direct mode during a start time. The invention also relates to an arrangement for driving a display device, to a display device which includes such an arrangement, to an electronic apparatus which is provided with a display device for the display of image data which includes an arrangement for driving the display unit, and to a method of starting a circuit arrangement 15 which includes a subvoltage generating unit 40, a voltage multiplier 20 and a start control unit 30. In order to enable reliable and fast starting of such a circuit arrangement 15 while effectively using the available current and space at the same time, it is proposed to switch the voltage multiplier 20 to a direct mode by means of an initial start signal 36 during an adaptive start time ts, the variation of an activation signal 32 generated in the start control unit 30 being monitored and the control of the voltage multiplier (20) taking place in dependence thereon.

Claims

1. A circuit arrangement for generating at least one voltage value, which circuit arrangement includes a subvoltage generating unit and a voltage multiplier, the subvoltage generating unit being arranged to switch the voltage multiplier to a direct mode in order to control the voltage multiplier during a start time;

the subvoltage generating unit comprising a plurality of intermediate nodes, each intermediate node formed by a series connection of a pair of resistors, and a plurality of switches, each switch coupled to one of the plurality of intermediate nodes;

wherein when the voltage multiplier is in direct mode the voltage multiplier is configured to connect a power supply node to an output of the voltage multiplier, and when the voltage multiplier is not in direct mode, the voltage multiplier is configured to disconnect the power supply node from the output of the voltage multiplier, and to connect the output of the voltage multiplier to an internal node for providing an internally generated output voltage.

2. The circuit arrangement as claimed in claim 1, characterized in that it is arranged to supply the voltage multiplier with an activation signal formed from a subvoltage generated by the subvoltage generating unit and from a reference signal, and that it is arranged to supply the voltage multiplier with an initial start signal formed from the activation signal during the start time.

3. The circuit arrangement as claimed in claim 1, characterized in that there is provided a start control unit for controlling the voltage multiplier, which start control unit includes at least one comparator and a logic unit, the comparator being arranged to compare a subvoltage generated by the subvoltage generating unit and a reference voltage, and to generate the activation signal, the logic unit generating an initial start signal so as to switch the voltage multiplier to a direct mode.

4. The circuit arrangement as claimed in claim 1, characterized in that the start time during which the voltage multiplier operates in a direct mode is adaptive adjustable.

5. The circuit arrangement as claimed in claim 1, characterized in that a series connection of switching devices of the stages in the voltage multiplier is closed in the direct mode, and that the capacitors associated with the stages can be disconnected.

6. The circuit arrangement of claim 1, wherein the plurality of switches comprises a plurality of transistors.

7. The circuit arrangement of claim 1, further comprising:

a first comparator coupled to the plurality of switches; and

a reference voltage source coupled to provide a reference voltage to the first comparator.

8. The circuit arrangement of claim 7, wherein the reference voltage source is a band gap circuit.

9. The circuit arrangement of claim 7, further comprising:

a second comparator coupled to the plurality of switches, and further coupled to the reference voltage source; and

a logic circuit coupled to receive an output signal from each of the first and second comparators;

wherein the first comparator and the second comparator receive different subvoltages from the plurality of switches.

10. A circuit arrangement for driving a display device, a subvoltage generating unit and a voltage multiplier, the subvoltage generating unit being arranged to control the voltage multiplier by switching the voltage multiplier to a direct mode by means of an initial start signal during a start time;

the subvoltage generating unit comprising a plurality of intermediate nodes, each intermediate node formed by a series connection of a pair of resistors, and a plurality of switches, each switch coupled to one of the plurality of intermediate nodes;

wherein when the voltage multiplier is in direct mode the voltage multiplier is configured to connect a power supply node to an output of the voltage multiplier, and when the voltage multiplier is not in direct mode, the voltage multiplier is configured to disconnect the power supply node from the output of the voltage multiplier, and to connect the output of the voltage multiplier to an internal node for providing an internally generated output voltage.

11. A circuit arrangement comprising:

a voltage multiplier for generating at least one voltage value, comprising a series connection of the first plurality of stages with first switching devices, second switching devices and capacitors, characterized in that during a start time the first switching devices are closed and by that a supply voltage at a first input of the voltage multiplier is switched to an output of the voltage multiplier; and

a subvoltage generating unit, coupled to the voltage multiplier, comprising a plurality of intermediate nodes, each intermediate node formed by a series connection of a pair of resistors, and a plurality of switches, each switch coupled to one of the plurality of intermediate nodes;

wherein subsequent to the start time, the first switches are opened and the supply voltage is disconnected from the output of the voltage multiplier.

12. A display unit for the display of image data, which display unit includes an arrangement for driving the display unit with a subvoltage generating unit and a voltage multiplier, the subvoltage generating unit being arranged to switch the voltage multiplier to a direct mode by means of at least one signal during a start time;

the subvoltage generating unit comprising a plurality of intermediate nodes, each intermediate node formed by a series connection of a pair of resistors, and a plurality of switches, each switch coupled to one of the plurality of intermediate nodes;

wherein when the voltage multiplier is in direct mode, the voltage multiplier is configured to connect a power supply node to an output of the voltage multiplier, and when the voltage multiplier is not in direct mode, the voltage multiplier is configured to disconnect the power supply node from the output of the voltage multiplier, and to connect the output of the voltage multiplier to an internal node for providing an internally generated output voltage.

13. An electronic apparatus which is provided with a display unit for the display of image data and also with an arrangement for driving the display unit, which arrangement includes a subvoltage generating unit and a voltage multiplier, the subvoltage generating unit being arranged that at least one signal controls the voltage multiplier and that the voltage multiplier can be switched to a direct mode during a start time;

the subvoltage generating unit comprising a plurality of intermediate nodes, each intermediate node formed by a series connection of a pair of resistors, and a plurality of switches, each switch coupled to one of the plurality of intermediate nodes;

wherein when the voltage multiplier is in direct mode the voltage multiplier is configured to connect a power supply node to an output of the voltage multiplier, and when the voltage multiplier is not in direct mode, the voltage multiplier is configured to disconnect the power supply node from the output of the voltage multiplier, and to connect the output of the voltage multiplier to an internal node for providing an internally generated output voltage.

14. A method of starting a circuit arrangement which includes a subvoltage generating unit and a voltage multiplier, in which method a first subvoltage value and a reference voltage are compared so as to generate an activation signal, the voltage multiplier being switched to a direct mode during a start time which is adaptively adjusted by monitoring an activation signal;

the subvoltage generating unit comprising a plurality of intermediate nodes, each intermediate node formed by a series connection of a pair of resistors, and a plurality of switches, each switch coupled to one of the plurality of intermediate nodes;

wherein when the voltage multiplier is in direct mode the voltage multiplier is configured to connect a power supply node to an output of the voltage multiplier, and when the voltage multiplier is not in direct mode, the voltage multiplier is configured to disconnect the power supply node from the output of the voltage multiplier, and to connect the output of the voltage multiplier to an internal node for providing an internally generated output voltage.

15. The method of claim 14, further comprising producing the reference voltage as an output of a band gap circuit.

16. The method of claim 15, wherein the subvoltage generating unit produces a plurality of subvoltages;

and further comprising selecting the first subvoltage value by means of a switching device.

17. The method of claim 16, further comprising selecting a second subvoltage by means of the switching device and concurrently providing the first subvoltage to a first comparator and the second subvoltage to a second comparator.

18. The method of claim 14, further comprising operating a logic circuit such that a signal is supplied to the voltage multiplier and the voltage multiplier, responsive to the signal, changes a voltage multiplication factor.