Abstract: A conversion circuit for converting a current signal into a first output voltage signal, where the current signal flows through a sensing component, is provided. The conversion circuit includes: a first current eliminating circuit, configured to eliminate a first current in the current signal. The first current eliminating circuit includes: a current sample and hold circuit; and a current driving circuit, coupled between the sensing component and the current sample and hold circuit; a second current eliminating circuit, coupled to the sensing component and configured to eliminate a second current in the current signal; and an integrating circuit, coupled to the sensing component and configured to integrate a third current in the current signal, and output a first input voltage signal between a first integration output terminal and a second integration output terminal.

Abstract: A current sample-and-hold circuit and a sensor, are provided. The current sample-and-hold circuit is used for offsetting a background photocurrent of a photodiode, and includes a capacitor and a first transconductance amplifier which has adjustable transconductance and outputs a sampled current to the photodiode to offset the background photocurrent of the photodiode. One end of the capacitor is connected with a power supply, the other end of the capacitor is connected with one end of the first transconductance amplifier; and the other end of the first transconductance amplifier is connected with the photodiode to output the sampled current to the photodiode. When the background photocurrent of the photodiode is increased, a change of a voltage of the capacitor within a large range can be avoided by increasing the transconductance of the first transconductance amplifier, so that the current sample-and-hold circuit can offset a larger background photocurrent.

Abstract: A fingerprint sensor and a terminal device are provided, including: a first drive circuit, configured to generate a periodic driving signal according to a periodic first input signal, periods of the first input signal and the driving signal being both a predetermined period; each second drive circuit corresponding to a column of voltage integrators respectively, the each second drive circuit being configured to generate a column select signal according to a second input signal, the column select signal being used for controlling an operating state of a corresponding column of voltage integrators; and each of N columns of voltage integrators configured to receive the driving signal and the column select signal generated by a corresponding second drive circuit, and charge or integrate a fingerprint capacitor according to the driving signal and the column select signal.

Abstract: A fingerprint sensor and a terminal device are provided. The fingerprint sensor includes a plurality of integration circuits (110) and a negative feedback circuit (120); the negative feedback circuit (120) is connected to the plurality of integration circuits (110) for respectively fixing an input common mode voltage of each of the integration circuits (110) as a reset bias voltage when the plurality of integration circuits (110) are in a reset phase; and each of the integration circuits (110) corresponds to a fingerprint capacitor respectively, and the integration circuit (110) is configured to perform integration processing on a charge of the corresponding fingerprint capacitor when in an integration phase, and output an output voltage related to the fingerprint capacitor. A fingerprint sensor and a terminal device of the present application could improve an SNR of a fingerprint image without increasing resources of a main control RAM.

Abstract: A signal conversion circuit, a heart rate sensor, and an electronic device are provided, and the signal conversion circuit includes: a photoelectric conversion circuit, configured to convert an optical signal into a current signal; a differential signal conversion circuit, connected to the photoelectric conversion circuit, and configured to convert the current signal into a first differential signal and a second differential signal, where the first differential signal is an integration signal of the current signal in a first phase, and the second differential signal is an integration signal of the current signal in a second phase; and a subtraction amplifier, connected to the differential signal conversion circuit, and configured to amplify a difference value between the first differential signal and the second differential signal, to generate a third differential signal. The signal conversion circuit of embodiments of the present disclosure can effectively suppress ambient interference.

Abstract: A correlated double sampling integrating circuit is provided. The circuit includes: a sampling and holding module, an energy storage unit and a feedback module. The sampling and holding module is configured to perform sampling and holding for different input signals. The energy storage unit is configured to store charges corresponding to the input signals upon the sampling and holding to generate node signals, and the feedback module is configured to form a negative feedback loop with the energy storage unit to control node signals at an integrating stage to keep consistent with node signals at a resetting stage and prevent output jump of the correlated double sampling integrating circuit. The correlated double sampling integrating circuit reduces noise, and prevents or weakens output jump of the correlated double sampling integrating circuit caused by the increase of the count of integrations.

Abstract: A current sampling and holding circuit is disclosed. The current sampling and holding circuit includes: a canceling circuit, connected in series between a VDD terminal and a current sensor, being conducted according to a first enable signal, and configured to output a current to cancel a direct-current component in the current sensor; and a mirroring circuit, connected in parallel between the VDD terminal and a ground voltage with the canceling circuit and the current sensor connected in series, and being conducted according to a second enable signal inverse to the first enable signal, and configured to perform current transfer according to a current difference between a mirror current of a shunt current and an output current of the current sensor. According to the present application, the setup speed of the current sampling and holding circuit is improved, and the noise output by the current sampling and holding circuit is reduced.

Abstract: An I-V conversion module includes: a current output type sensor, a pre-integral circuit, a charge transfer auxiliary circuit, and an I-V transformation circuit including an inverting amplifier. The current output type sensor is connected to an input end of the I-V transformation circuit through the pre-integral circuit. The charge transfer auxiliary circuit connects in parallel with the inverting amplifier. When both the pre-integral circuit and the charge transfer auxiliary circuit are open circuits, the pre-integral circuit pre-integrates the induction current output by the current output type sensor to store pre-integral charges. When both pre-integral circuit and the charge transfer auxiliary circuit are closed circuits, the pre-integral charges are transferred to the I-V transformation circuit. In these embodiments, both the time for establishing the I-V conversion module and power consumption can be reduced.

Abstract: An I-V converting module includes: a current output sensor, an I-V transforming circuit, a sampling and holding circuit, a source follower, a loop switch, and a bypass circuit. A drain of the source follower is connected to an input/output end of the sampling and holding circuit. A source of the source follower is connected to an input end of the I-V transforming circuit and an output end of the current output sensor, and a gate of the source follower is connected to an output end of the I-V transforming circuit via the loop switch, and to the bypass circuit. When the loop switch is closed and the bypass circuit is disabled, a feedback loop formed by the source follower, the I-V transforming circuit and the loop switch is conducted, and the I-V converting module enters into a sampling setup stage.

Abstract: A trigger, includes: a first voltage input terminal; a bias voltage input terminal; a first bias transistor having a scaling of N to a first component of an external device; a comparator transistor having a scaling of N to a second component of the external device; a first switch transistor and a second switch transistor; a shunt transistor having a control terminal connected to the first voltage input terminal, a second terminal connected to the second terminal of the second switch transistor, and a first terminal connected to the first terminal of the comparator transistor. The shunt transistor has an enlarging scale of M to the comparator transistor. A voltage output terminal is respectively connected to the second terminal of the first switch transistor, the control terminal of the second switch transistor, and the second terminal of the comparator transistor.

Abstract: An amplitude limiting oscillation circuit (100) is disclosed. The amplitude limiting oscillation circuit (100) includes: an oscillation circuit (110), configured to generate an oscillation signal; a pulse width modulation circuit (120), configured to generate a pulse width modulation signal according to an amplitude of the oscillation signal; a low pass filtering circuit (130), configured to convert the pulse width modulation signal into a direct current control voltage signal, where the direct current control voltage signal is configured to control a voltage controlled resistance circuit (140); and the voltage controlled resistance circuit (140), configured to change a resistance value of the voltage controlled resistance circuit (140) according to under the direct current control voltage signal, to control the amplitude of the oscillation signal. The amplitude limiting oscillation circuit (100), may improve performance of the amplitude limiting oscillation circuit (100).

Abstract: An amplifying circuit includes a reference voltage generating circuit, a common-mode voltage conversion circuit, a common-mode negative feedback circuit, and an amplifying sub-circuit. The reference voltage generating circuit generates a first reference voltage, a second reference voltage, and a reference common-mode voltage according to a post-stage common-mode voltage. The common-mode voltage conversion circuit converts the pre-stage output differential signal into a differential input signal according to the reference common-mode voltage. The common-mode negative feedback circuit generates a control voltage to quickly establish a common-mode negative feedback of the amplifying sub-circuit, wherein the first reference voltage and the second reference voltage are used to cancel a baseline signal of the pre-stage output differential signal. The amplifying circuit can eliminate the baseline signal, convert the common-mode voltage and quickly establish the common-mode negative feedback.

Abstract: Embodiments of the present disclosure provide a capacitive fingerprint sensor. The capacitive fingerprint sensor includes: a first electrode plate layer, a second electrode plate layer and a third electrode plate layer that are sequentially arranged. The first electrode plate layer forms a fingerprint capacitor with a finger, at least one fourth electrode plate layer is arranged between the first electrode plate layer and the second electrode plate layer, a first parasitic capacitor is formed between the first electrode plate layer and the fourth electrode plate layer, and a second parasitic capacitor is formed between the second electrode plate layer and the fourth electrode plate layer; and the capacitive fingerprint sensor further comprises an integrator having an integrating capacitor, and the integrating capacitor is formed between the second electrode plate layer and the third electrode plate layer.

Abstract: Embodiments of the present disclosure hereinafter provide a capacitive fingerprint sensor. The capacitive fingerprint sensor includes: an integrator, a trigger and a base cancelling circuit; where the integrator is configured to store charges from a fingerprint capacitor to generate an output signal and transfer the output signal to the trigger, the trigger is configured to trigger the base cancelling circuit to generate a base cancelling signal and output the base cancelling signal to the integrator if the output signal exceeds a predetermined threshold, and the base cancelling signal is used to adjust the output signal of the integrator to fall within the predetermined threshold. In this way, the integrator is prevented from simply coming to saturation, and thus a dynamic range of the integrator is increased.

Abstract: A current sampling and holding circuit is disclosed. The current sampling and holding circuit includes: a canceling circuit, connected in series between a VDD terminal and a current sensor, being conducted according to a first enable signal, and configured to output a current to cancel a direct-current component in the current sensor; and a mirroring circuit, connected in parallel between the VDD terminal and a ground voltage with the canceling circuit and the current sensor connected in series, and being conducted according to a second enable signal inverse to the first enable signal, and configured to perform current transfer according to a current difference between a mirror current of a shunt current and an output current of the current sensor. According to the present application, the setup speed of the current sampling and holding circuit is improved, and the noise output by the current sampling and holding circuit is reduced.

Abstract: An I-V converting module includes: a current output sensor, an I-V transforming circuit, a sampling and holding circuit, a source follower, a loop switch, and a bypass circuit. A drain of the source follower is connected to an input/output end of the sampling and holding circuit. A source of the source follower is connected to an input end of the I-V transforming circuit and an output end of the current output sensor, and a gate of the source follower is connected to an output end of the I-V transforming circuit via the loop switch, and to the bypass circuit. When the loop switch is closed and the bypass circuit is disabled, a feedback loop formed by the source follower, the I-V transforming circuit and the loop switch is conducted, and the I-V converting module enters into a sampling setup stage.

Abstract: A conversion circuit for converting a current signal into a first output voltage signal, where the current signal flows through a sensing component, is provided. The conversion circuit includes: a first current eliminating circuit, configured to eliminate a first current in the current signal. The first current eliminating circuit includes: a current sample and hold circuit; and a current driving circuit, coupled between the sensing component and the current sample and hold circuit; a second current eliminating circuit, coupled to the sensing component and configured to eliminate a second current in the current signal; and an integrating circuit, coupled to the sensing component and configured to integrate a third current in the current signal, and output a first input voltage signal between a first integration output terminal and a second integration output terminal.

Abstract: An amplifying circuit includes a reference voltage generating circuit, a common-mode voltage conversion circuit, a common-mode negative feedback circuit, and an amplifying sub-circuit. The reference voltage generating circuit generates a first reference voltage, a second reference voltage, and a reference common-mode voltage according to a post-stage common-mode voltage. The common-mode voltage conversion circuit converts the pre-stage output differential signal into a differential input signal according to the reference common-mode voltage. The common-mode negative feedback circuit generates a control voltage to quickly establish a common-mode negative feedback of the amplifying sub-circuit, wherein the first reference voltage and the second reference voltage are used to cancel a baseline signal of the pre-stage output differential signal. The amplifying circuit can eliminate the baseline signal, convert the common-mode voltage and quickly establish the common-mode negative feedback.

Abstract: A trigger, includes: a first voltage input terminal; a bias voltage input terminal; a first bias transistor having a scaling of N to a first component of an external device; a comparator transistor having a scaling of N to a second component of the external device; a first switch transistor and a second switch transistor; a shunt transistor having a control terminal connected to the first voltage input terminal, a second terminal connected to the second terminal of the second switch transistor, and a first terminal connected to the first terminal of the comparator transistor. The shunt transistor has an enlarging scale of M to the comparator transistor. A voltage output terminal is respectively connected to the second terminal of the first switch transistor, the control terminal of the second switch transistor, and the second terminal of the comparator transistor.