CN112712776B

CN112712776B - Voltage amplifying circuit and related voltage method

Info

Publication number: CN112712776B
Application number: CN201911015782.5A
Authority: CN
Inventors: 赵世伟; 钟建川; 王智伟
Original assignee: YUANJING TECHNOLOGY CO LTD; Himax Technologies Ltd
Current assignee: YUANJING TECHNOLOGY CO LTD; Himax Technologies Ltd
Priority date: 2019-10-24
Filing date: 2019-10-24
Publication date: 2022-04-26
Anticipated expiration: 2039-10-24
Also published as: CN112712776A

Abstract

The invention provides a voltage amplifying circuit and a related voltage amplifying method, wherein the voltage amplifying circuit can be applied to a liquid crystal diffuser driver and comprises a signal generator, a mixer and an amplifier. The signal generator is used for generating an input signal; the mixer is used for mixing the input signal with an analog voltage to generate an intermediate input signal with a first voltage range; the amplifier is used for converting the intermediate input signal into an output signal with a second voltage range in a rail-to-rail mode, wherein the second voltage range is larger than the first voltage range.

Description

Voltage amplifying circuit and related voltage method

Technical Field

The present invention relates to a voltage amplifying circuit applied to a Liquid Crystal (LC) diffuser driver and a related voltage amplifying method thereof, and more particularly, to a phase control scheme applied to a liquid crystal product.

Background

Operational amplifiers (Op-amps) are capable of generating up to several hundred times larger output potentials based on input potentials, and are derived from analog computers and used to perform mathematical operations on linear, nonlinear, and frequency-dependent (frequency-dependent) circuits.

Based on the multivariate characteristics, operational amplifiers are commonly used in analog circuits and as functional blocks, various characteristics of the operational amplifier, such as its gain, input impedance, output impedance, bandwidth, etc., are determined by external elements by using negative feedback, and have less influence by temperature coefficient or engineering tolerance (engineering tolerance) of the operational amplifier itself.

In addition, an operational amplifier is one of the most commonly used electronic devices at present, and is widely used in a client, an industrial application, and a scientific instrument. However, how to effectively apply the operational amplifier to the lcd diffuser driver is still an important issue in the art, and there is a need for a novel method and related apparatus for improving the efficiency of applying the operational amplifier to the lcd diffuser driver.

Disclosure of Invention

An embodiment of the present invention provides a voltage amplifying circuit, which can be applied to a Liquid Crystal (LC) diffuser driver and includes a signal generator, a mixer and an amplifier. The signal generator is used for generating an input signal; the mixer is used for mixing the input signal with an analog voltage to generate an intermediate input signal with a first voltage range; the amplifier is used for converting the intermediate input signal into an output signal with a second voltage range in a Rail-to-Rail (Rail-to-Rail) mode, wherein the second voltage range is larger than the first voltage range.

An embodiment of the present invention provides a voltage amplifying method applied to a liquid crystal diffuser driver, including: generating an input signal; mixing the input signal with an analog voltage by using a mixer to generate an intermediate input signal with a first voltage range; and converting the intermediate input signal into an output signal having a second voltage range in a rail-to-rail manner, wherein the second voltage range is greater than the first voltage range.

Drawings

Fig. 1 is a block diagram illustrating a design concept of a voltage amplifying circuit according to an embodiment of the invention.

Fig. 2 is a schematic diagram of a detailed architecture based on the concept of fig. 1 according to an embodiment of the present invention.

Fig. 3A to 3D are schematic diagrams of respective waveforms of different output signals of the voltage amplifying circuit shown in fig. 2 under different design requirements.

FIG. 3E is a diagram of a set of stepped output waveforms according to a specific design requirement.

FIG. 4 is a flowchart of a voltage amplifying method according to an embodiment of the invention.

[ notation ] to show

1 signal generating unit

2 phase control unit

3 programmable output voltage unit

4 Signal processing unit

5 slew rate control unit

6 drive kernel unit

7 high voltage side control unit

8 Low Voltage side control Unit

9 feedback control unit

10 output drive unit

11 equivalent circuit

100. 200 voltage amplifying circuit

210 signal generator

220 phase control unit

230D/A converter

240 equivalent circuit module

S _1 input signal

S _2 phase control signal

S0-S2 signal selection port

OPA _ 1-OPA _4 operational amplifier

MX _ 1-MX _4 mixer

VX selects an analog voltage

LV _ VDD supply voltage

GND ground voltage

S _ IN intermediate input signal

S _ OUT output signal

LCA-LCD waveform

400 method

402 to 410 steps

High voltage side of HV

Low voltage side of LV

Detailed Description

Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This description and the appended claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. Also, the term "coupled" is used herein to encompass any direct or indirect electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.

Referring to fig. 1, fig. 1 is a block diagram illustrating a design concept of a voltage amplifying circuit 100 according to an embodiment of the invention. As shown in fig. 1, the driver core (shown as the driver core unit 6) can adjust the upper half and the lower half of the output driver (shown as the output driver unit 10) according to the signal provided by the mixer (shown as the signal processing unit 4). The signal output by the output driver may be used as a liquid crystal diffuser drive signal. The waveforms (including the frequency and amplitude) of these output signals can be appropriately adjusted by a slew rate control program shown by the slew rate control unit 5. In addition, the output of the output driving unit 10 can be further coupled to an equivalent circuit (equivalent circuit), as shown in the equivalent circuit unit 11.

Referring to fig. 2, fig. 2 is a schematic diagram illustrating a detailed architecture based on the concept of fig. 1 according to an embodiment of the invention. As shown in fig. 2, the voltage amplifying circuit 200 is applied to a liquid crystal diffuser driver, and the voltage amplifying circuit 200 includes a signal generator 210, a phase control unit 220, a digital-to-analog converter (DAC) 230, an equivalent circuit module 240, and four amplifying paths (hereinafter referred to as first to fourth amplifying paths), where each amplifying path includes a mixer and an operational amplifier (op-amp). For example, the first amplification path includes a mixer MX _1 and an operational amplifier OPA _1, the second amplification path includes a mixer MX _2 and an operational amplifier OPA _2, the third amplification path includes a mixer MX _3 and an operational amplifier OPA _3, and the fourth amplification path includes a mixer MX _4 and an operational amplifier OPA _ 4. The signal generator 210 is configured to generate an input signal S _1 to the phase control unit 220, wherein the signal generator 210 may be an example of the signal generating unit 1 shown in fig. 1. The phase control unit 220 is coupled between the signal generator 210 and a corresponding mixer (e.g., the mixer MX _1 of the first amplification path), and is configured to control the respective phases of the first to fourth amplification paths by generating the phase control signal S _ 2. Please note that the phase control unit 220 can be an example of the phase control unit 2 shown in FIG. 1, any one of the mixers MX _1 MX _4 can be an example of the signal processing unit 4 shown in FIG. 1, and any one of the operational amplifiers OPA _1 OPA _4 can be an example of the blocks 6-10 shown in FIG. 1. Please note that the blocks 6-10 shown in FIG. 1 are for illustrative purposes only and are not intended to limit the scope of the present invention. For example, any one of the operational amplifiers OPA _ 1-OPA _4 may further include elements other than the blocks 6-10. In another example, any one of the operational amplifiers OPA _ 1-OPA _4 does not necessarily include all of the blocks 6-10, and some blocks may be omitted according to actual design requirements.

Each of the mixers MX _1 to MX _4 is configured to mix the input signal S _1 (or the phase control signal S _2) with the analog voltage VX supplied from the digital-to-analog converter 230 to generate an intermediate input signal S _ IN having a first voltage range to a corresponding operational amplifier (e.g., the operational amplifier OPA _1 IN the first amplification path), wherein the digital-to-analog converter 230 is an example of the programmable output voltage unit 3 shown IN fig. 1, and the magnitude of the analog voltage VX is between the supply voltage LV _ VDD and the ground voltage GND. For example, the magnitude of the analog voltage VX may be between 0V and 5V (or other predetermined values) based on the selected signal port (e.g., one of the signal selection ports S0-S2), but the invention is not limited thereto. IN addition, each of the operational amplifiers OPA _1 to OPA _4 is configured to convert the intermediate input signal S _ IN at the low voltage side (labeled "LV") into the output signal S _ OUT IN a rail-to-rail manner with a second voltage range, wherein the second voltage range at the high voltage side (labeled "HV") is larger than the first voltage range. For example, the second voltage range can be 0-100V. The signal selection ports S0-S2 are used to select one of the analog voltage VX, the supply voltage LV VDD and the ground voltage GND as a specific signal, wherein the value of the intermediate input signal S _ IN generated by the mixers MX _ 1-MX _4 is based on the selection signal.

In addition to the signals at the signal selection ports S0-S2, the DAC 230 may select other possible predetermined signals having voltages between S0, S1, and S2. For example, the dac 230 may select signals other than S0 and S1 by using a digital signal between GND and VDD. Therefore, the voltage amplifying circuit of the invention has more flexible and diversified purposes and improves the convenience of users.

An output signal (e.g., S _ OUT) of a general operational amplifier is easily distorted by an internal resistance, resulting in difficulty in reaching a high voltage. With respect to this situation, the term "rail-to-rail" refers to the conversion between the output voltage and the output voltage being linear without distortion. The rail-to-rail design provides various user-friendly benefits to the operational amplifier circuit, such as low distortion, low noise, high bandwidth gain (bandwidth gain), power savings, and the like. In particular, cross distortion (cross distortion) is a common problem in operational amplifiers. Given that the bias voltage provided by a circuit is low and the input signal to the op amp is also low, the output waveform is more likely to be distorted. However, even when the operational amplifier is subject to, for example, low supply current and low signal slew rate (slew rate), the rail-to-rail operational amplifier may still provide a certain degree of bandwidth. For example, a rail-to-rail operational amplifier provided with amplifiers OPA _1 to OPA _4 can effectively solve the above-mentioned problems.

The equivalent circuit block 240 can be replaced by various circuit designs, and the output terminals of the operational amplifiers OPA _ 1-OPA _4 can be selectively coupled to the equivalent circuit block 240. Although only the output terminals of the operational amplifiers OPA _1 and OPA _3 are coupled to the equivalent circuit module 240 in the embodiment of fig. 2, the invention is not limited thereto. In other cases, the output terminals of the operational amplifiers OPA _ 1-OPA _4 can be all coupled to the equivalent circuit block 240, wherein the equivalent circuit block 240 can be an example of the equivalent circuit 11 shown in FIG. 1.

Referring to fig. 3A to 3D, fig. 3A to 3D are schematic diagrams respectively illustrating respective waveforms of different output signals of the voltage amplifying circuit shown in fig. 2 under different design requirements. As shown in fig. 3A to 3D, the LCA to LCD represent waveforms of output signals of the first to fourth amplification paths shown in fig. 2, respectively. With appropriate adjustments, the waveforms LCA-LCD can be presented in a variety of different waveforms, such as Sine (Sine), square (square), triangle (triangle), and sawtooth (sawtooth), among others.

Fig. 3A is a schematic diagram of a first scenario, in which the output phases of the first and second amplification paths are opposite to each other, and the outputs of the third and fourth amplification paths are turned off.

Fig. 3B is a schematic diagram of a second scenario, which is just opposite to the first scenario, wherein the output phases of the third and fourth amplification paths are opposite to each other, and the outputs of the first and second amplification paths are turned off.

FIG. 3C is a diagram of a third scenario, which is equivalent to the combination of the first scenario and the second scenario, wherein the outputs of the first to fourth amplification paths are not turned off.

Fig. 3D is a schematic diagram of a fourth scenario, in which the first to fourth amplification paths respectively output square waves with different phases, the output phase of the second amplification path is shifted by a specific amount compared to the output phase of the first amplification path, the output phase of the third amplification path is shifted by the specific amount compared to the output phase of the second amplification path, and the output phase of the fourth amplification path is shifted by the specific amount again compared to the output phase of the third amplification path, so that the waveforms do not overlap each other.

Referring to fig. 3E, fig. 3E is a schematic diagram of a set of stepped output waveforms according to a specific design requirement, wherein the voltage at the output terminal of the first amplification path is reduced by half (e.g., from 100V to 50V) within 0-25% of the duty cycle, and is reduced by the remaining half (e.g., from 50V to 0V) again within 25-50% of the duty cycle. In addition, the voltage at the output end of the second amplification path is reduced by half within 50-75% of the duty cycle, and is reduced by the remaining half again within 75-100% of the duty cycle. The step output waveform is applied to a liquid crystal diffuser driver, and is particularly suitable for operation at high voltages (e.g., 10V-100V). Turning off the high voltage once (one-shot) may cause the liquid crystal to not respond instantaneously, i.e., dropping sharply from the high voltage (e.g., 100V) to a low voltage (e.g., 0V) causes the liquid crystal to rotate for only a short period of time, in which case the liquid crystal will likely rotate only a fraction of the desired extent. By using two-step closed waveform (or more steps to form a step), the waveform provided by the invention can make the liquid crystal respond in real time

The operation of the

voltage amplifying circuit

100 or 200 can be summarized in fig. 4. Fig. 4 is a flow chart of a voltage amplification method 400 according to an embodiment of the invention. Please note that if substantially the same result is obtained, the following steps need not be performed exactly in the order of FIG. 4, and the method 400 is summarized as follows:

step 402: starting;

step 404: converting the analog voltage into a digital signal;

step 406: mixing an input signal with the analog voltage to generate an operational amplifier (OPA) input signal;

step 408: converting the operational amplification input signal into a multipath frequency-adjustable operational amplification output signal in a rail-to-rail mode;

step 410: the frequency-adjustable operation is used to amplify the output signal to adjust the liquid crystal diffuser.

The operation of the

voltage amplifying circuits

100 and 200 is illustrated in the above-mentioned voltage amplifying method, and since the implementation details of each step can be easily understood by those skilled in the art after reading the paragraphs related to the

voltage amplifying circuits

100 and 200, the detailed description of the method 400 is omitted here for the sake of brevity.

The above-mentioned embodiments are only preferred embodiments of the present invention, and all equivalent changes and modifications made by the claims of the present invention should be covered by the scope of the present invention.

Claims

1. A voltage amplifying circuit applied to a Liquid Crystal (LC) diffuser driver, comprising:

a signal generator for generating an input signal;

a mixer for mixing the input signal with an analog voltage to generate an intermediate input signal having a first voltage range; and

an amplifier for converting the intermediate input signal to an output signal having a second voltage range in a Rail-to-Rail (Rail-to-Rail) manner, wherein the second voltage range is greater than the first voltage range;

the mixer is an adjustable mixer selectively coupled to the analog voltage, a supply voltage (supply voltage), and a ground voltage, wherein the analog voltage is between the supply voltage and the ground voltage.

2. The voltage amplification circuit of claim 1, further comprising:

a digital-to-analog converter (DAC) is used to convert a digital signal into the analog voltage.

3. The voltage amplification circuit of claim 1, further comprising:

a plurality of selection ports for selecting one of the analog voltage, the supply voltage, and the ground voltage as a specific signal, wherein a value of the intermediate input signal generated by the mixer is based on the specific signal.

4. The voltage amplification circuit of claim 1, wherein the amplifier is a Rail-to-Rail (Rail) operational amplifier (op-amp).

5. The voltage amplification circuit of claim 1, wherein the mixer and the amplifier form a first amplification path, and the voltage amplification circuit further comprises:

at least one second amplification path; and

and a phase control unit coupled between the signal generator and the mixer, the phase control unit controlling the phase of the first amplification path and the phase of the second amplification path respectively.

6. The voltage amplification circuit of claim 5, further comprising:

a third amplification path and a fourth amplification path;

wherein the first to fourth amplification paths output square waves (square waves), wherein an output phase of the first amplification path is in phase with an output phase of the third amplification path, an output phase of the second amplification path is in phase with an output phase of the fourth amplification path, and the output phase of the first amplification path is in anti-phase with the output phase of the second amplification path.

7. The voltage amplification circuit of claim 5, further comprising:

a third amplification path and a fourth amplification path;

the first to fourth amplification paths respectively output square waves with different phases, wherein the output phase of the second amplification path is different from the output phase of the first amplification path by a specific amount, the output phase of the third amplification path is different from the output phase of the second amplification path by the specific amount, and the output phase of the fourth amplification path is different from the output phase of the third amplification path by the specific amount.

8. The voltage amplifying circuit as claimed in claim 5, wherein the output voltage of the first amplifying path is regulated down by half in 0-25% duty cycle (duty cycle) and by the other half in 25-50% duty cycle.

9. The voltage amplification circuit of claim 8, wherein the output voltage of the second amplification path is regulated down by half in 50-75% duty cycle and by the other half in 75-100% duty cycle.