Sample and hold circuit and digital-to-analog converter circuit

A technology of sampling and holding circuit and sampling voltage, which is applied in the direction of digital-to-analog converter, electrical analog memory, logic circuit connection/interface layout, etc., which can solve the problems of output error and achieve the effect of small output error

Active Publication Date: 2010-01-20
RENESAS ELECTRONICS CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0028] Although the circuit specification of the serial DAC is small, in order to reduce the area of ​​the DAC corresponding to the digital driver, if it is reduced in Figure 16 If the capacitance values ​​of the capacitors C91 and C92 for charge distribution in the serial DAC of the serial DAC, the input capacitance (mainly gate capacitance) of the amplifier 919 (voltage follower) affects the charge distribution between C91 and C92, resulting in an output error (this Inventor's Analysis)

Method used

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  • Sample and hold circuit and digital-to-analog converter circuit
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  • Sample and hold circuit and digital-to-analog converter circuit

Examples

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Embodiment 1

[0065] figure 1 It is a figure which shows the structure of one Example of this invention. It has n-channel MOS transistors M1 and M2, load circuit 15, amplifier stage 16, sampling voltage supply circuit 17, current sources M3 and M4, capacitors C11 and C12, and switches 110, 120, 121, 122. n channel. The MOS transistors M1 and M2, the load circuit 15, the differential stage constituted by the current sources M3 and M4, the amplifier stage 16, and the switches 120, 121, 122 constitute a differential circuit.

[0066] The drains of the n-channel MOS transistors M1 and M2 constituting the differential input stage are connected to the power supply node N2 of the power supply VDD through the load circuit 15, the sources are respectively connected to the power supply node N1 of the low-voltage power supply VSS through the current sources M3 and M4, and the gate poles are connected to nodes N7, N8. Capacitance Cg1 , Cg2 between nodes N7 , N8 and VSS represents gate parasitic cap...

Embodiment 2

[0098] Image 6 yes means Figure 5 The diagram of the configuration of the application circuit of , switches the non-inverting input / inverting input of the differential pair (M1, M2) at a predetermined cycle. exist Figure 5 In , the gate of the MOS transistor M1 is an inverting input, and the gate of the MOS transistor M2 is a non-inverting input, but in this embodiment, they are switched at a predetermined cycle.

[0099] refer to Image 6 , has: a switch 124, connected between the output node N9 and the gate (node ​​N8) of the MOS transistor M2; a switch 123, connected between the gate of the MOS transistor M2 and one end (node ​​N2) of the capacitor C12; switch 111 , connected between one end (node ​​N11) of capacitor C11 and node N5; switch 117, connected between one end (node ​​N12) of capacitor C12 and node N5; switch 118, connected between one end (node ​​N11) and node N5 of capacitor C11 Between the nodes N6; the switch 112 is connected between one end of the cap...

Embodiment 3

[0111] Figure 8 It is a figure which shows the structure of the 3rd Example of this invention. In the present embodiment, the sampling voltage supply circuit 17C controls ON / OFF of the switches 113 and 114 based on the bit data of the digital signal serially input during the sampling period. There is a switch 114 between the node N4 and the node N11, and a switch 113 between the node N11 and the node N3. The current values ​​of the current sources M3 and M4 are set to be equal to each other, and the capacitance values ​​of the capacitors C11 and C12 are set to be equal to each other. The sampling voltage supply circuit 17C may be connected to the node N8.

[0112] Figure 9 It is explained from the point of view of switch control Figure 8 diagram of the action. The period T0-T2 is a data sampling period, the switch 121 is turned on, and the switches 120 and 122 are turned off.

[0113] In the period T0-T2 (reset period), the switches 110 and 113 are turned on and the s...

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Abstract

The present invention provides a sample and hold circuit and a serial DAC with high precision output. Even the capacitance value of the capacitor for executing charge allocation is low, the output error caused by the input capacitance (grid capacitance) of an amplifier is lower. The sample and hold circuit comprises the following components: capacitance elements (C11,C12) for allocating charges through a switch (110); a differential circuit; an amplifying grade (16) which is input with the output of the differential circuit and has an output connected with the output terminal (N9); and a sampling voltage supply circuit (17) which provides a sampling voltage to one end of at least one element selected from the capacitance elements (C11,C12). The differential circuit comprises the followingcomponents: a MOS transistor (M1); a MOS transistor (M2); and a load circuit (15) which is connected between the drains of the first and second MOS transistors (M1,M2) and a terminal of a second power supply.

Description

technical field [0001] The invention relates to a sampling and holding circuit and a digital-to-analog conversion circuit. Background technique [0002] Recently, among display devices, liquid crystal display devices (LCDs) characterized by thinness, lightness, and low power consumption have been widely popularized, and are widely used in mobile phones (mobile-phone, cell-phone), PDA (personal digital assistant) , notebook PC and other mobile devices display unit. Recently, however, liquid crystal display devices have been increased in size and technologies for moving image applications have been improved, and they are not only used in mobile devices, but also can be implemented in large-screen display devices of the placement type and large-screen liquid crystal televisions. As these liquid crystal display devices, active matrix drive type liquid crystal display devices capable of high-definition display are used. [0003] First, refer to Figure 15 A typical configuratio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G11C27/02H03K19/0185H03M1/66G09G3/20H03F3/45
CPCG11C27/024
Inventor 土弘
Owner RENESAS ELECTRONICS CORP
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