Semiconductor integrated circuit with voltage generation circuit, liquid crystal display controller and mobile electric equipment
First Claim
1. A display system comprising:
- a display panel having first and second electrodes; and
a display controller on a semiconductor substrate, the display controller coupled to the first and the second electrodes of the display panel, the display controller comprising;
a power supply circuit coupled to receive an external source voltage and generating a positive voltage higher than the external source voltage and a negative voltage lower than a ground potential, the positive voltage and the negative voltage being applied to the second electrodes of the display panel;
a first wiring feeding the negative voltage as a bias voltage to the semiconductor substrate;
a second wiring supplying the ground potential;
a switch element coupled between the first wiring and the second wiring;
a circuit which generates a first control signal to make the switch element conduct temporarily in accordance with a second control signal for starting up the power supply circuit; and
a terminal coupled to receive the negative voltage generated from the power supply circuit; and
a diode whose anode coupled to the terminal of the display controller and whose cathode coupled to the ground potential.
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Accused Products
Abstract
There is to be provided a liquid crystal drive controller with a built-in power supply circuit wherein latch-up is made difficult to arise even if one amplitude level of the segment line drive voltage is set to the ground potential and the levels of other liquid crystal drive voltages are determined accordingly. A semiconductor integrated circuit with a built-in power supply circuit, wherein a negative voltage generated in a power supply circuit is applied to a substrate or a well region as a bias voltage, is provided with a switch for temporarily applying the ground potential to the substrate or well region to be biased with the negative voltage at the time of starting up the power supply circuit.
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Citations
13 Claims
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1. A display system comprising:
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a display panel having first and second electrodes; and a display controller on a semiconductor substrate, the display controller coupled to the first and the second electrodes of the display panel, the display controller comprising; a power supply circuit coupled to receive an external source voltage and generating a positive voltage higher than the external source voltage and a negative voltage lower than a ground potential, the positive voltage and the negative voltage being applied to the second electrodes of the display panel; a first wiring feeding the negative voltage as a bias voltage to the semiconductor substrate; a second wiring supplying the ground potential; a switch element coupled between the first wiring and the second wiring; a circuit which generates a first control signal to make the switch element conduct temporarily in accordance with a second control signal for starting up the power supply circuit; and a terminal coupled to receive the negative voltage generated from the power supply circuit; and a diode whose anode coupled to the terminal of the display controller and whose cathode coupled to the ground potential. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A display system comprising:
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a display panel having first electrodes and second electrodes; a display controller on a semiconductor substrate, the display controller comprising; a power supply circuit coupled to receive an external source voltage, the power supply circuit generating a voltage to be applied to the first electrodes of the display panel and generating a positive voltage higher than the external source voltage or a negative voltage lower than a ground potential, the positive voltage and the negative voltage being to be applied to the second electrodes of the display panel; a first wiring feeding the negative voltage as a bias voltage to the semiconductor substrate; a second wiring supplying the ground potential; a switch element coupled between the first wiring and the second wiring; a circuit which generates a first control signal to make the switch element conduct temporarily in accordance with a second control signal for starting up the power supply circuit; a first drive circuit which supplies signals for driving the first electrodes of the display panel on the basis of a voltage generated by the power supply circuit; and a second drive circuit which supplies signals for driving the second electrodes of the display panel on the basis of a voltage generated by the power supply circuit; and a terminal coupled to receive the negative voltage generated from the power supply circuit; and a diode whose anode coupled to the terminal of the display controller and whose cathode coupled to the ground potential. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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Specification