Nuvoton Technology Corporation

Yeh-Tai Hung

Chung Ming Hsieh

Te-Ming Tseng

Wen-Yi Li

Po-Sheng Chen

Chung-He Li

Wei-Chan Hsu

Ching-Yen Chiu

Hua-Chun Tseng

Tu-Yiin Chang

Hui-Chun Wang

A signal conversion device for converting a single-ended input voltage into a differential input voltage having a positive input voltage and a negative input voltage is provided. During a sampling phase, a holding phase, and a common-mode voltage generation phase, a capacitor related to the positive input voltage is electrically connected to the single-ended input voltage, and a capacitor related to the negative input voltage is electrically connected to a preset voltage. During a single-ended to differential phase, the capacitor related to the positive input voltage is electrically connected to the preset voltage, and the capacitor related to the negative input voltage is electrically connected to the single-ended input voltage. Hence, the common-mode voltage is not related to a capacitance ratio, and the capacitors does not need to be designed as switching capacitors with multiple switches. No complex control is required, and the parasitic effect of the circuit can be reduced.

Signal conversion device and circuit system using the same

An embodiment of the present disclosure provides a conversion circuit for converting a single-ended input to a differential input, which has fewer switches and fewer capacitors. This conversion circuit increases the signal-to-noise ratio (SNR), and the conversion circuit directly uses the higher supply voltage AVDD without being bucked by the regulator, wherein the common mode voltage is AVDD/2N, and N is greater than 1. Overall, not only the circuit area is smaller and the SNR is higher, but also the manufacturing cost is reduced. In addition, compared with the prior art, the conversion circuit of the embodiment of the present disclosure has only three operation periods, so the control is simpler and the operation speed is faster.

Conversion circuit for converting single input to differential input and system circuit using the same

A reference current/voltage generator includes a current mirror unit and a current-mode temperature compensation unit. The current mirror unit generates a first current, a first sum current and a second sum current flowing through first to third terminals thereof, and the first current, the first sum current and the second sum current are in a multiple relationship. The current-mode temperature compensation unit is electrically connected to the second and third terminals of the current mirror unit, and when a voltage on the second terminal is equal to a voltage on the third terminal, the first sum current is a sum of a current proportional to absolute temperature (PTAT) and a current complementary to absolute temperature (CTAT). The first terminal of the current mirror unit is an output terminal of the reference current/voltage generator and configured to output the first current as a reference current.

Reference current/voltage generator and circuit system using the same

A reference voltage circuit is disclosed. In the reference voltage circuit, a comparator compares a reference voltage and a voltage of a capacitor, so as to output a comparison signal; a controller checks conditions of the reference voltage and the leakage current based on the comparison signal; when a voltage of the capacitor is reduced too quickly, the controller adjusts a switching frequency of a switch device to effectively maintain the voltage of the capacitor.

Reference voltage circuit

A protection circuit is adapted to a switching-capacitor regulation circuit having a capacitor. The protection circuit comprises a current source, first and second switch circuits, and a control unit. First, the control unit turns on the second switch circuit to make a top end and a bottom end of the capacitor, and control the first switch circuit to make the current source no connect the capacitor, and then set a voltage of the top and the bottom to be a first preset voltage. Next, the control unit turns off the second switch circuit to disconnect the top end and the bottom end, and turn on the first switch circuit to flow current from the bottom end of the capacitor. When a voltage difference between the top end and the bottom end is equal to a preset initial voltage, the control unit control the first switch circuit to disconnect the current source and the capacitor; next, the control unit controls current flow in or out from the top of the capacitor based on the voltage on the top of the capacitor.

Protection circuit and operation method thereof

A startup circuit initializes a voltage of a capacitor of a switch-capacitor regulator. The startup circuit includes a voltage forming circuit and a control unit. The voltage forming circuit selectively electrically connected to the top and the bottom of the capacitor. In a first operation phase, the voltage forming circuit is electrically connected to the top and bottom of the capacitor, and the top and bottom of the capacitor are connected to each other, and the voltages of the top and bottom are set as a preset high voltage. In a second operation phase, the voltage forming circuit disconnects the top and the bottom, and generates current flowing out from the bottom of the capacitor until the voltage cross the capacitor is equal to the preset initial voltage. In the third operation phase, the startup circuit is disconnected from the capacitor.

Start-up circuit and operation method thereof

Provided is a system for testing a reference voltage circuit applicable to a reference voltage circuit. The reference voltage circuit includes a bandgap reference voltage circuit, switching elements, a first capacitor, a second capacitor and a comparator. The testing system includes a control logic unit. In a test mode, the control logic unit adjusts an allowable value of the comparator to speed up the suitability test of the switching elements.

System and method for testing reference voltage circuit

A voltage detection circuit is disclosed. The voltage detection circuit includes a threshold voltage detection circuit, a current leakage compensation circuit and a low voltage detection circuit. The threshold voltage detection circuit detects the voltage of a power source and determines whether the voltage is dropped over a threshold voltage, so as to wake up the low voltage detection circuit. The current leakage compensation circuit determines whether a voltage difference between the first voltage and the second voltage exceeds a preset value, so as to generate a trigger signal to activate the low voltage detection circuit. As a result, the voltage detection circuit can have high efficiency and low power consumption, and can detect the voltage drop more accurately in environment with current leakage, temperature variation, or process variation.

Voltage detection circuit

The present disclosure illustrates a low-power voltage detection circuit, including a threshold voltage detection circuit, a leakage detection circuit and a low-voltage detection circuit. By utilizing the above-mentioned threshold voltage detection circuit and leakage detection circuit, the voltage variations caused by leakage, temperature or process can be detected in the more efficient and power saving way.

Low-power voltage detection circuit

A reference voltage circuit is provided, which includes bandgap reference circuit, bias current generator, first capacitor, second capacitor, comparator and control logic circuit. In the active mode of the control logic circuit, the control logic circuit controls the bandgap reference circuit to deliver bandgap reference voltage. The comparator transmits first comparison signal to control logic circuit when the first and second capacitors are charged to the bandgap reference voltage. The control logic circuit enters low power mode and controls the bandgap reference circuit to stop delivering the bandgap reference voltage. If the comparator detects the potential difference between the first capacitor and second capacitor exceeds the threshold value, the control logic circuit returns to active mode according to the second comparison signal transmitted form the comparator.

Growing community of inventors

Hsinchu, Taiwan

Yeh-Tai Hung