A low-leakage rectifying unit

Abstract

The utility model aims at providing a kind of high energy efficiency, with weak energy collection and high integration, small size's low leakage rectifier unit.The utility model includes field effect tube and operational amplifier, the drain electrode of field effect tube is connected with power input terminal, the source of field effect tube is connected with output terminal, the output terminal of operational amplifier is connected with the grid of field effect tube, the opposite input terminal of operational amplifier is connected with power input terminal by feedback resistance, the same phase input terminal of operational amplifier is connected with the source of field effect tube, the source of field effect tube is also connected with output energy storage capacitor.The utility model is applied to the technical field of circuit structure.

Description

Technical Field

[0001] This invention relates to the technical field of circuit structure, and in particular to a low-leakage rectifier unit. Background Technology

[0002] The rectifier unit is a key circuit structure that converts alternating current (AC) to direct current (DC), and it is widely used in power management, energy harvesting, wireless charging, and sensor power supply. To ensure the effective operation of the rectifier unit, additional control circuitry is usually included, and this circuitry needs to be powered. In this type of circuitry, the leakage caused by the on-state voltage drop does not need to be considered. However, traditional circuit structures are insufficient to meet the requirements of structural simplification and high integration needed for innovative products. Under these requirements, a rectifier unit capable of self-powered regulation is needed. The high efficiency and low leakage performance of the rectifier unit are particularly important when setting up a self-powered system with energy harvesting capabilities, as this directly affects energy conversion efficiency and system availability. Commercially available rectifier units are typically composed of diodes or MOSFETs, and the main circuit structures include half-wave rectification, full-wave rectification, bridge rectification, and synchronous rectification. Common ordinary diodes and Schottky diodes have on-state voltage drops, and these large voltage drops are unsuitable for the voltage required by the downstream rechargeable battery. For example, some Schottky diodes, such as the 1N5817, have a leakage current of about 50uA at room temperature and are not suitable for self-powered systems.

[0003] Therefore, if a rectifier unit with high energy efficiency, weak energy harvesting, high integration, miniaturization, and low leakage can be provided, it can well meet the requirements of highly integrated and miniaturized electronic products for rectifier units. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a high-efficiency, low-leakage rectifier unit with weak energy harvesting, high integration, and miniaturization.

[0005] The technical solution adopted by this utility model is as follows: This utility model includes a field-effect transistor (FET) and an operational amplifier. The drain of the FET is connected to the power input terminal, the source of the FET is connected to the output terminal, the output terminal of the operational amplifier is connected to the gate of the FET, the inverting input terminal of the operational amplifier is connected to the power input terminal through a feedback resistor, the non-inverting input terminal of the operational amplifier is connected to the source of the FET, and the source of the FET is also connected to an output energy storage capacitor.

[0006] As can be seen from the above scheme, the main function of the field-effect transistor (FET) is rectification. By setting the operational amplifier to control the FET, the rectification effect is ensured. The output voltage after rectification by the FET can provide power to the operational amplifier, thus eliminating the need for an external power supply. Simultaneously, by setting the output energy storage capacitor, energy can be stored, enabling the operational amplifier to be powered even with a small input signal such as thermoelectric or piezoelectric signals (0.005VAC). The FET can also self-charge using the energy after rectification, thereby achieving long-term, stable rectification control without the need for external power supply.

[0007] In a preferred embodiment, the feedback resistor includes a first resistor and a second resistor, the first resistor being connected between the power input terminal and the inverting input terminal of the operational amplifier, and the second resistor being connected between the first resistor and the gate of the field-effect transistor.

[0008] A preferred embodiment is that the resistance of the first resistor and the resistance of the second resistor are in a ratio of 1:8 to 1:16.

[0009] A preferred embodiment is that the resistance value of the first resistor is in a ratio of 1:12 to the resistance value of the second resistor.

[0010] In a preferred embodiment, the positive power supply terminal of the operational amplifier is connected to the output energy storage capacitor, and the negative power supply terminal of the operational amplifier is grounded.

[0011] A preferred embodiment is that the operational amplifier is a low-power operational amplifier chip of model TS1001. Attached Figure Description

[0012] Figure 1 This is the circuit schematic diagram of this utility model. Detailed Implementation

[0013] like Figure 1As shown, in this embodiment, the present invention includes a field-effect transistor (FET) Q1 and an operational amplifier IC1. The drain of the FET Q1 is connected to the power input terminal VIN, and the source of the FET Q1 is connected to the output terminal VOUT. The output terminal of the operational amplifier IC1 is connected to the gate of the FET Q1. The inverting input terminal of the operational amplifier IC1 is connected to the power input terminal VIN through a feedback resistor, and the non-inverting input terminal of the operational amplifier IC1 is connected to the source of the FET Q1. An output energy storage capacitor C1 is also connected to the source of the FET Q1. The FET Q1 is a low-threshold P-type FET of model BSH205, and the operational amplifier IC1 is a low-power operational amplifier chip of model TS1001. The power input terminal VIN is connected to the AC signal terminal, which can be used for environmental energy conversion, input signals, or integrated energy harvesting modules, such as light energy, heat energy, and vibration energy. The field-effect transistor Q1 can provide active rectification with a voltage drop as low as 0.8V, and the rectified output voltage can power the operational amplifier IC1, thereby obtaining the lowest reverse leakage current. At even lower voltages, the body diode of the field-effect transistor Q1 becomes a regular diode. In the rectifier unit provided by this invention, the forward voltage drop is only 40mV or lower, and the reverse leakage in the circuit is less than that of a Schottky diode. The leakage current of synchronous rectification or ideal diodes can be as low as nA, reducing energy waste. It is suitable for weak energy harvesting, supports mV-level input, and the zero-threshold field-effect transistor or the self-starting charge pump rectification realized through the output energy storage capacitor C1 can handle small signals such as thermoelectric and piezoelectric signals, such as 0.05V AC signal input. In addition, this invention eliminates the need for battery maintenance, and the low leakage design extends the self-discharge time from hours to months when the output energy storage capacitor C1 is selected as a supercapacitor.

[0014] In this embodiment, the feedback resistor includes a first resistor R1 and a second resistor R2. The first resistor R1 is connected between the power input terminal VIN and the inverting input terminal of the operational amplifier IC1, and the second resistor R2 is connected between the first resistor R1 and the gate of the field-effect transistor Q1. The resistance ratio of the first resistor R1 to the second resistor R2 is between 1:8 and 1:16.

[0015] In this embodiment, the resistance ratio of the first resistor R1 to the second resistor R2 is 1:12. When there is a positive voltage between the power input terminal VIN and the output terminal VOUT, the operational amplifier IC1 turns on the field-effect transistor Q1, which satisfies... , where V GATE V is the gate drive voltage of the field-effect transistor Q1. IN It is the input voltage at the power input terminal VIN, V OUTIt is the output voltage of the output terminal VOUT.

[0016] From the source and drain voltage relationship of the field-effect transistor Q1, we can obtain: V DS = V IN -V OUT V GS = V GATE -V OUT VDS is the voltage between the source and drain of the field-effect transistor Q1, and VGS is the voltage between the gate and source of the field-effect transistor Q1.

[0017] In this embodiment, the first resistor R1 = 100K ohms, the second resistor R2 = 1.2M ohms, and the output energy storage capacitor C1 = 10uF.

[0018] V can be obtained GS =-(R2 / R1)V DS When the resistance ratio of the first resistor R1 to the second resistor R2 is 1:12, a 40mV voltage drop across the drain-source voltage of the field-effect transistor Q1 is sufficient to turn it on with a small drain current. Choosing a higher ratio can further reduce the voltage drop, keeping it within the 6mV worst-case input offset voltage limit of the operational amplifier IC1. The operational amplifier IC1 is powered by the output energy storage capacitor C1. The operational amplifier IC1 is rail-to-rail input and output, and there is no phase reversal issue when operating close to the power rail. The operational amplifier IC1 operates at a voltage as low as 0.8V. The non-inverting input of the operational amplifier IC1 is directly connected to the gate of the field-effect transistor Q1. The rectifier unit consumes slightly more than 1uA with active rectification of a 100Hz sine wave, and its leakage current is less than that of most Schottky diodes.

[0019] The bandwidth of the operational amplifier IC1 limits the rectifier unit to lower frequency signals. When the bandwidth exceeds 500Hz, the gain of the operational amplifier IC1 begins to decrease. As the signal frequency increases, the field-effect transistor Q1 remains consistently off, and its body diode performs the rectification function. A fast-fall-time input may draw reverse current from the field-effect transistor Q1; however, for small currents, Q1 operates below a threshold, and the gate-source voltage has an exponential relationship with the drain-source current, causing the operational amplifier IC1 to turn off quickly. The limiting factor is the amplifier's slew rate of 1.5V / ms. As long as the load on the operational amplifier IC1 is not excessive, allowing Q1 to enter its linear region, the reverse current will not exceed the forward current.

[0020] In this embodiment, the positive power supply terminal of the operational amplifier IC1 is connected to the output energy storage capacitor C1, and the negative power supply terminal of the operational amplifier IC1 is grounded.

[0021] Although the embodiments of this utility model are described with reference to actual solutions, they do not constitute a limitation on the meaning of this utility model. For those skilled in the art, modifications to the implementation schemes and combinations with other schemes based on this specification are obvious.

Claims

1. A low-leakage rectifier unit, characterized in that: It includes a field-effect transistor (Q1) and an operational amplifier (IC1). The drain of the field-effect transistor (Q1) is connected to the power input terminal (VIN), and the source of the field-effect transistor (Q1) is connected to the output terminal (VOUT). The output terminal of the operational amplifier (IC1) is connected to the gate of the field-effect transistor (Q1). The inverting input terminal of the operational amplifier (IC1) is connected to the power input terminal (VIN) through a feedback resistor. The non-inverting input terminal of the operational amplifier (IC1) is connected to the source of the field-effect transistor (Q1). The source of the field-effect transistor (Q1) is also connected to an output energy storage capacitor (C1).

2. The low-leakage rectifier unit according to claim 1, characterized in that: The feedback resistor includes a first resistor (R1) and a second resistor (R2). The first resistor (R1) is connected between the power input terminal (VIN) and the inverting input terminal of the operational amplifier (IC1), and the second resistor (R2) is connected between the first resistor (R1) and the gate of the field-effect transistor (Q1).

3. A low-leakage rectifier unit according to claim 2, characterized in that: The resistance value of the first resistor (R1) and the resistance value of the second resistor (R2) are in a ratio of 1:8 to 1:

16.

4. A low-leakage rectifier unit according to claim 3, characterized in that: The resistance value of the first resistor (R1) is in a ratio of 1:12 to the resistance value of the second resistor (R2).

5. A low-leakage rectifier unit according to claim 1, characterized in that: The positive power supply terminal of the operational amplifier (IC1) is connected to the output energy storage capacitor (C1), and the negative power supply terminal of the operational amplifier (IC1) is grounded.

6. A low-leakage rectifier unit according to claim 1, characterized in that: The operational amplifier (IC1) is a low-power operational amplifier chip with the model number TS1001.

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