TWI708238B - Voltage amplifying circuit and associated voltage amplifying method - Google Patents

Abstract

The present invention provides a voltage amplifier circuit and associated voltage amplifying method. The voltage amplifier circuit includes a signal generator, a mixer and an amplifier. The signal generator is arranged to generate an input signal; the mixer is arranged to mix the input signal with an analog signal to generate an intermediate input signal having a first voltage range; and the amplifier is arranged to convert 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 larger than the first voltage range.

Description

Voltage amplifier circuit and related voltage method

The present invention relates to a voltage amplification circuit applied to a liquid crystal (LC) diffuser driver and a related voltage amplification method applied to a liquid crystal (LC) diffuser driver, in particular to a phase control scheme applied to liquid crystal products .

Operational amplifiers (Op-amps for short) can generate output potentials up to hundreds of times larger based on input potentials. In addition, operational amplifiers originated from analog computers and are used for linear, non-linear, and frequency-dependent ) The circuit performs mathematical operations.

Based on multiple characteristics, operational amplifiers are commonly used in analog circuits and used as functional blocks. By using negative feedback, various characteristics of operational amplifiers, such as its gain, input impedance, output impedance, bandwidth, etc. It is determined by external components and is less affected by temperature coefficient or engineering tolerance of the operational amplifier itself.

In addition, operational amplifiers are currently one of the most commonly used electronic devices, and are widely used in clients, industrial applications, and scientific instruments. However, how to effectively apply operational amplifiers to liquid crystal diffuser drivers is still an important issue in this field, so there is a need for novel methods and phases. Close the device to improve the efficiency of the operational amplifier applied to the LCD diffuser driver.

An embodiment of the present invention provides a voltage amplifying circuit that 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 to generate an input signal; the mixer is used to mix the input signal with an analog voltage to generate an intermediate input signal with a first voltage range; the amplifier is used to The rail-to-rail method converts the intermediate input signal into an output signal having a second voltage range, wherein the second voltage range is greater than the first voltage range.

An embodiment of the present invention provides a voltage amplification method applied to a liquid crystal diffuser driver, including: generating an input signal; using a mixer to mix the input signal with an analog voltage to generate a An intermediate input signal of the 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.

1: Signal generation unit

2: Phase control unit

3: Programmable output voltage unit

4: Signal processing unit

5: Slew rate control unit

6: Drive the core 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 amplifier circuit

210: signal generator

220: phase control unit

230: digital analog 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: select analog voltage

LV_VDD: supply voltage

GND: Ground terminal voltage

S_IN: Intermediate input signal

S_OUT: output signal

LCA~LCD: Waveform

400: method

402~410: steps

HV: high voltage side

LV: low voltage side

FIG. 1 is a block diagram of the design concept of a voltage amplifier circuit according to an embodiment of the present 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.

Figures 3A to 3D are schematic diagrams of respective waveforms of different output signals of the voltage amplifier circuit shown in Figure 2 under different design requirements.

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

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

In the specification and subsequent patent applications, certain words are used to refer to specific elements. Those with general knowledge in the field should understand that hardware manufacturers may use different terms to refer to the same components. The scope of this specification and subsequent patent applications does not use differences in names as a way to distinguish elements, but uses differences in functions of elements as a criterion for distinguishing. The "include" mentioned in the entire manual and subsequent requests is an open term, so it should be interpreted as "include but not limited to". In addition, the term "coupling" here includes any direct and indirect electrical connection means. Therefore, if it is described that a first device is coupled to a second device, it means that the first device can be directly electrically connected to the second device, or indirectly electrically connected to the second device through other devices or connection means.

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

Please continue to refer to Figure 2. Figure 2 is a schematic diagram of a detailed architecture based on the concept of Figure 1 according to an embodiment of the present invention. As shown in Figure 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 A digital-to-analog converter (DAC) 230, an equivalent circuit module 240, and four amplification paths (hereinafter referred to as the first to fourth amplification paths), each of which includes a mixer And an operational amplifier (op-amp). For example, the first amplification path includes the mixer MX_1 and the operational amplifier OPA_1, the second amplification path includes the mixer MX_2 and the operational amplifier OPA_2, the third amplification path includes the mixer MX_3 and the operational amplifier OPA_3, and the fourth The amplification path includes the mixer MX_4 and the operational amplifier OPA_4. The signal generator 210 is used to generate the input signal S_1 to the phase control unit 220, where the signal generator 210 may be an example of the signal generation unit 1 shown in FIG. 1. The phase control unit 220 is coupled between the signal generator 210 and a corresponding mixer (for example, the mixer MX_1 on the first amplifying path), and is used to control the second signal by generating the phase control signal S_2 The respective phases of the first to fourth amplification paths. Please note that the phase control unit 220 can be an example of the phase control unit 2 shown in FIG. 1, and any one of the mixers MX_1~MX_4 can be an example of the signal processing unit 4 shown in FIG. Any of the amplifiers OPA_1 to OPA_4 can be an example of the blocks 6 to 10 shown in FIG. 1. Please note that the blocks 6-10 shown in Fig. 1 are for example purposes only, and are not intended to limit the scope of the present invention. For example, any of the operational amplifiers OPA_1 to OPA_4 may further include components other than blocks 6 to 10. In another example, any one of the operational amplifiers OPA_1 to OPA_4 does not necessarily include all the blocks in the blocks 6 to 10, and some blocks can be omitted according to actual design requirements.

Each of the mixers MX_1~MX_4 is used to mix the input signal S_1 (or the phase control signal S_2) with the analog voltage VX transmitted from the digital-to-analog converter 230, so as to generate an intermediate with a first voltage range (intermediate) input signal S_IN to a corresponding operational amplifier (for example, operational amplifier OPA_1 in the first amplification path), where the digital-to-analog converter 230 may be 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. Any one of the mixers MX_1~MX_4 can be an adjustable mixer For example, based on the selected signal port (such as one of the signal selection ports S0~S2), the analog voltage VX can range from 0V to 5V (or other predetermined values). However, the present invention does not Limit this. In addition, each of the operational amplifiers OPA_1~OPA_4 is used to convert the intermediate input signal S_IN on the low voltage side (labeled as "LV") into an output signal S_OUT having a second voltage range in a rail-to-rail manner. The second voltage range on the high voltage side (labeled "HV") is greater 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. The value of the intermediate input signal S_IN generated by the mixers MX_1~MX_4 is based on this Select the signal.

In addition to the above-mentioned signals located in the signal selection ports S0~S2, the digital-to-analog converter 230 can also select other possible predetermined signals whose magnitude is between the voltage values of S0, S1, and S2. For example, the digital-to-analog converter 230 can select signals other than S0 and S1 by using a digital signal between GND and VDD. In this way, the application of the voltage amplifier circuit of the present invention will be more flexible and diversified, and the convenience of users will be improved.

The output signal of a general operational amplifier (such as S_OUT) is easily distorted due to the influence of internal resistance, which makes it difficult to achieve high voltage. In contrast to this situation, the so-called "rail-to-rail" means that the conversion between output voltage and output voltage is linear without distortion. The rail-to-rail design can provide operational amplifier circuits with various user-friendly benefits, such as low distortion, low noise, bandwidth gain, power saving, and so on. In particular, crossover distortion is a common problem in operational amplifiers. Assuming that the bias voltage provided by a circuit is low and the input signal of the operational amplifier is also low, the output waveform is more likely to cause distortion. However, even when the operational amplifier is facing low supply current and low signal slew rate, rail-to-rail operational amplifier can still improve Provide a certain degree of bandwidth. For example, rail-to-rail operational amplifiers with amplifiers OPA_1~OPA_4 can effectively solve the above problems.

The equivalent circuit module 240 can be replaced by various circuit designs, and the output terminals of the operational amplifiers OPA_1 to OPA_4 can be selectively coupled to the equivalent circuit module 240. Although in the embodiment of FIG. 2, only the output terminals of the operational amplifiers OPA_1 and OPA_3 are coupled to the equivalent circuit module 240, the present invention is not limited to this. In other cases, the output terminals of the operational amplifiers OPA_1 to OPA_4 can be fully coupled to the equivalent circuit module 240, where the equivalent circuit module 240 can be an example of the equivalent circuit 11 shown in FIG.

Please refer to Figures 3A to 3D. Figures 3A to 3D are schematic diagrams of the respective waveforms of different output signals of the voltage amplifier circuit shown in Figure 2 under different design requirements. As shown in Figures 3A to 3D, LCA~LCD respectively represent the waveforms of the output signals of the first to fourth amplification paths shown in Figure 2. With proper adjustments, the waveform LCA~LCD can be presented in a variety of different waveforms, such as sine, square, triangle, sawtooth, and so on.

FIG. 3A is a schematic diagram of the first scenario, in which the output phase of the first amplification path and the output phase of the second amplification path are opposite to each other, and the outputs of the third amplification path and the fourth amplification path are closed.

Figure 3B is a schematic diagram of the second scenario, which is exactly the opposite of the first scenario, where the output phase of the third amplification path and the output phase of the fourth amplification path are opposite to each other, and the first amplification path and the The output of the second amplification path is closed.

Figure 3C is a schematic diagram of the third scenario, which is equivalent to the combination of the first scenario and the second scenario, where the outputs of the first to fourth amplification paths are not closed.

Figure 3D is a schematic diagram of the fourth scenario, in which the first to fourth amplification paths output square waves with different phases, and the output phase of the second amplification path is shifted by a certain amount compared to the output phase of the first amplification path. The output phase of the third amplifying path is also shifted by the specific amount compared to the output phase of the second amplifying path, and the output phase of the fourth amplifying path is shifted again by the specific amount compared to the output phase of the third amplifying path In this way, these waveforms will not overlap each other.

Please refer to Figure 3E. Figure 3E is a schematic diagram of a set of stepped output waveforms according to a specific design requirement. The voltage at the output terminal of the first amplification path is reduced during the 0-25% duty cycle. It is reduced by half (for example, reduced from 100V to 50V), and is reduced again by the remaining half (for example, reduced from 50V to 0V) in the 25-50% duty cycle. In addition, the voltage at the output terminal of the second amplification path is reduced by half during the 50~75% duty cycle, and is reduced again by the remaining half during the 75~100% duty cycle. This stepped output waveform is applied to a liquid crystal diffuser driver, especially suitable for high voltage operation (for example, 10V~100V). Turning off the high voltage one-shot may cause the liquid crystal to fail to respond instantly, that is, a sudden drop from a high voltage (such as 100V) to a low voltage (such as 0V) makes the liquid crystal only short. Time to rotate, in this case, most of the liquid crystal only rotates a part of the expected degree. By turning off the waveform in two segments (or more segments to form a stepped shape), the waveform provided by the present invention enables the liquid crystal to respond instantly

The operation of the voltage amplifier circuit 100 or 200 can be summarized in Figure 4. FIG. 4 is a flowchart of a voltage amplification method 400 according to an embodiment of the invention. Please note that if you can get substantially the same results, the following steps do not need to be implemented exactly in the order of Figure 4. The method 400 is summarized as follows: Step 402: Start; Step 404: Convert the analog voltage to a digital signal; Step 406: Mix the input signal with the analog voltage to generate an operational amplifier (OPA) input signal; Step 408: Use rail to rail The operation amplified input signal is converted into a multi-path frequency-adjustable operation amplified output signal; Step 410: Use the adjustable frequency operation to amplify the output signal to perform liquid crystal diffuser adjustment.

The above voltage amplification method enumerates the operations of the voltage amplification circuits 100 and 200. After reading the paragraphs related to the voltage amplification circuits 100 and 200, ordinary knowledge in the field can easily understand the implementation details of each step. For the sake of brevity, The detailed description of the method 400 is omitted here. The foregoing descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made in accordance with the scope of the patent application of the present invention shall fall within the scope of the present invention.

200: Voltage amplifier circuit

210: signal generator

220: phase control unit

230: digital analog 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: select analog voltage

LV_VDD: supply voltage

GND: Ground terminal voltage

S_IN: Intermediate input signal

S_OUT: output signal

LCA~LCD: Waveform

HV: high voltage side

LV: low voltage side

Claims (10)

A voltage amplifier circuit, applied to a liquid crystal (LC) diffuser driver, includes: a signal generator for generating an input signal; a mixer for mixing the input signal with an analog voltage Frequency to generate an intermediate input signal with a first voltage range; and an amplifier for converting the intermediate input signal into an output signal with a second voltage range in a rail-to-rail manner , Wherein the second voltage range is greater than the first voltage range. The voltage amplifier circuit according to claim 1, further comprising: a digital-to-analog converter (DAC) for converting a digital signal into the analog voltage. The voltage amplifier circuit of claim 2, wherein the mixer is a tunable mixer selectively coupled to the analog voltage, a supply voltage and a ground voltage, wherein the The magnitude of the analog voltage is between the supply voltage and the ground voltage. The voltage amplifier circuit according to claim 3, 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 the mixer is The value of the intermediate input signal generated is based on the specific signal. The voltage amplifier circuit according to claim 1, wherein the amplifier is a rail-to-rail (Rail-to-Rail) operational amplifier (op-amp). The voltage amplifier circuit of claim 1, wherein the mixer and the amplifier form a first amplifier path, and the voltage amplifier circuit further includes: at least one second amplifier path; and a phase control unit coupled to Between the signal generator and the mixer, the phase control unit is used for controlling the phase of the first amplification path and the phase of the second amplification path respectively. The voltage amplifier circuit according to claim 6, further comprising: a third amplifier path and a fourth amplifier path; wherein the first to fourth amplifier paths output square waves, and the first amplifier path The output phase of the third amplification path is in phase with the output phase of the third amplification path, the output phase of the second amplification path is in phase with the output phase of the fourth amplification path, and the output phase of the first amplification path is in phase with the second amplification The output phase of the path is reversed. The voltage amplifying circuit according to claim 6, further comprising: a third amplifying path and a fourth amplifying path; wherein the first to fourth amplifying paths respectively output square waves of different phases, and the second amplifying path The output phase 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 differs by the specific amount. The voltage amplifying circuit of claim 6, wherein the output voltage of the first amplifying path is reduced by half during a 0-25% duty cycle (duty cycle), and is reduced within a 25-50% duty cycle The other half. The voltage amplifying circuit of claim 9, wherein the output voltage of the second amplifying path is reduced by half during the 50~75% duty cycle, and reduced by the other half during the 75~100% duty cycle.

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