TOUCH SENSING METHOD AND ASSOCIATED CIRCUIT
First Claim
1. A display controller fabricated on a semiconductor substrate, comprising:
- a touch control circuit that asserts a touch reset signal and detects whether a contact point is touched; and
a pulse width modulation (PWM) circuit coupled to the touch control circuit to generate a PWM signal, the touch reset signal and the PWM signal associated with an image synchronous signal.
4 Assignments
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Accused Products
Abstract
A touch sensing method and associated circuit are provided. In one aspect, a touch control circuit includes a first current source, a second current source, a plurality of switches, a hysteresis comparator, a frequency divider and a flip-flop. The switches are couple to a plurality of external contact points. The hysteresis comparator is coupled to a first reference comparison voltage and a second reference comparison voltage. Each of the external contact points is selectively coupled to an input terminal of the hysteresis comparator through the switches. The first current source and the second current source are coupled to the input terminal of the hysteresis comparator to generate a sensing voltage. The hysteresis comparator compares the sensing voltage with the first reference comparison voltage and the second reference comparison voltage to generate a hysteresis comparison output to control the first current source or the second current source.
21 Citations
20 Claims
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1. A display controller fabricated on a semiconductor substrate, comprising:
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a touch control circuit that asserts a touch reset signal and detects whether a contact point is touched; and a pulse width modulation (PWM) circuit coupled to the touch control circuit to generate a PWM signal, the touch reset signal and the PWM signal associated with an image synchronous signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A touch sensing method applied to a display controller fabricated on a semiconductor substrate, the method comprising:
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generating a touch reset signal associated with an image synchronous signal; generating a sensing voltage with a sensing frequency in response to the touch reset signal corresponding to a contact point; and determining whether the contact point is touched according to the sensing frequency. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A touch control circuit as an integrated part of a display controller, the touch control circuit comprising:
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a first current source; a second current source; a plurality of switches coupled to a plurality of external contact points; and a hysteresis comparator, coupled to a first reference comparison voltage and a second reference comparison voltage, selectively coupled to one of the external contact points through the switches, the hysteresis comparator having an input terminal coupled to the first current source and the second current source to generate a sensing voltage, the hysteresis comparator comparing the sensing voltage with the first reference comparison voltage and the second reference comparison voltage to generate a hysteresis comparison output to control the first current source and the second current source. - View Dependent Claims (20)
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Specification