Low-voltage high-performance acquisition system

Abstract

The invention discloses a low-voltage high-performance acquisition system, which belongs to the field of integrated circuits, and comprises a programmable gain amplifier, a gain adjusting module, an ADC (Analog to Digital Converter) and a clock generating module, the programmable gain amplifier, the ADC and the clock generation module all work under a first voltage, the gain adjustment module works under a second voltage, and a voltage difference exists between the first voltage and the second voltage. The charge pump circuit designed by the invention can be used by all gain gear switches, and the clock generation is also based on the existing clock generation module, so that the cost is relatively low, and meanwhile, a high-performance acquisition effect can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuits, and in particular to a low-voltage and high-performance acquisition system. Background Art

[0002] like Figure 1 As shown in Figure 1, traditional high-performance acquisition systems are usually composed of high-performance PGA (programmable gain amplifier) ​​and high-precision ADC. By adjusting the gain, the range can be automatically converted to improve the measurement accuracy to better meet the requirements of the system.

[0003] In actual circuits, the gain adjustment function is achieved by adjusting the equivalent resistance of the feedback resistor module in the PGA. Switches in the signal path often cause linearity problems, especially in low-voltage applications. When the signal variation range is relatively large, linearity optimization is often difficult and costly. In this context, there is an urgent need for an acquisition system that can effectively improve linearity at low voltages. Summary of the invention

[0004] The purpose of the present invention is to provide a low-voltage and high-performance data acquisition system to solve the problems in the background technology.

[0005] In order to solve the above technical problems, the present invention provides a low-voltage high-performance acquisition system, including: a programmable gain amplifier, a gain adjustment module, an ADC, and a clock generation module; The programmable gain amplifier, the ADC, and the clock generation module all operate at a first voltage, and the gain adjustment module operates at a second voltage. There is a voltage difference between the first voltage and the second voltage.

[0006] In one implementation, the second voltage is generated by a charge pump circuit and is used to supply power to the gate terminal of the gain adjustment module.

[0007] In one embodiment, the charge pump and the ADC are provided with clock sources through a clock generation module; the ADC samples when the sampling clock is high and integrates when the integration clock is high; the clock of the charge pump is after the sampling ends and before the integration starts.

[0008] The present invention provides a low-voltage high-performance acquisition system, which designs a charge pump circuit for use with all gain gear switches, and the clock generation is also based on the existing clock generation module, which is relatively low in cost and can achieve high-performance acquisition effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a schematic diagram of the traditional acquisition system structure.

[0010] Figure 2 It is a structural schematic diagram of the low-voltage high-performance acquisition system provided by the present invention.

[0011] Figure 3 It is a schematic diagram of the structure of the PGA gain gear adjustment module provided by the present invention.

[0012] Figure 4 This is a schematic diagram of the clock timing provided by the present invention. DETAILED DESCRIPTION

[0013] The following is a further detailed description of a low voltage high performance acquisition system proposed by the present invention in combination with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer according to the following description. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0014] The present invention proposes an acquisition system. For low-voltage applications with high requirements on linearity, the new acquisition system can reduce the design difficulty of PGA (programmable gain amplifier) ​​gear adjustment.

[0015] like Figure 2 The figure shows the structure diagram of the acquisition system of the present invention. Power A is the normal working voltage of the chip. PGA, ADC, and clock module Clock generator all work under Power A voltage. The new acquisition system designs the gear adjustment module of PGA under Power B voltage, and uses the voltage difference between Power A voltage and Power B voltage to reduce the design difficulty of PGA gear adjustment switch and improve linearity. Because for low-voltage applications, Power A itself is a relatively low voltage, the switch impedance will be relatively high, especially under different process angles, to obtain a relatively small impedance, the switch size will be relatively large.

[0016] like Figure 3 The figure shows a PGA gain level adjustment module. In the present invention, a Charge Pump circuit is specially designed to generate Power B, which is used to power the gate end of the PGA level adjustment switch. This can greatly reduce the difficulty of switch design and more easily improve the linearity of the overall acquisition system.

[0017] The charge pump needs a clock source when it is designed. In high-precision applications, the timing of the clock used by each module may affect the sampling of the signal. For example, the clock of the charge pump will cause jitter of the PGA output signal. If the ADC samples the PGA output signal before the signal is recovered, the acquisition accuracy of the entire acquisition system will be affected. The present invention specifically designs the clock timing of the entire acquisition system, which in principle avoids mutual interference between different modules. Figure 4 As shown, the ADC samples when the sampling clock is high and integrates when the integration clock is high. The present invention designs the charge pump clock after the sampling is completed and before the integration begins, so that the switching of the charge pump clock each time avoids the sampling moment, avoiding the PGA output signal from being sampled by the subsequent ADC when it is interfered by the charge pump clock jump, thereby reducing the sampling error.

[0018] The acquisition system of the present invention includes a PGA, a PGA gain adjustment module, a charge pump of its power supply module, an ADC, and a clock generation module. The PGA gain adjustment module reduces the overall switch impedance by increasing the switch gate voltage, thereby reducing the impedance variation range caused by signal changes and improving the overall linearity. Since the charge pump generates a high voltage requiring a clock signal, according to Figure 4 Designing the timing of the entire acquisition system based on the timing in the data acquisition system can effectively reduce the error caused by the charge pump to the acquisition system.

[0019] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A low voltage high performance acquisition system, characterized in that: include: Programmable gain amplifier, gain adjustment module, ADC, clock generation module; The programmable gain amplifier, the ADC, and the clock generation module all operate at a first voltage, and the gain adjustment module operates at a second voltage. There is a voltage difference between the first voltage and the second voltage.

2. The low voltage high performance acquisition system according to claim 1, characterized in that: The second voltage is generated by a charge pump circuit and is used to supply power to the gate terminal of the gain adjustment module.

3. The low voltage high performance acquisition system as claimed in claim 2, characterized in that: The charge pump and the ADC are provided with clock sources through a clock generation module; the ADC performs sampling when the sampling clock is high and performs integration when the integration clock is high; the clock of the charge pump is after the sampling ends and before the integration starts.

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