43 results about "Forward voltage" patented technology

Device for controlling at least one light-emitting diode (LED1) to generate short light pulses (LP),- with an H-bridge (H) consisting of a first half-bridge (HB1: T1, T2) with a first transistor (T1) and a second transistor (T2) and a second half-bridge (HB2: T2, T3) with a third transistor (T3) and a fourth transistor (T4),- wherein the H-bridge (H) is controlled by a control unit (ST) and- wherein the H-bridge (H) can be operated by the control unit (ST) in pulsed mode (GPB) and in quasi-continuous mode (QDB) and- wherein the first half-bridge (HB1: T1, T2) is supplied with electrical energy from a first positive supply voltage (VCC1) and a first negative supply voltage (GND1) and- wherein the second half-bridge (HB2: T3,T4) is supplied with electrical energy from a second positive supply voltage (VCC2) and a second negative supply voltage (GND2) and- wherein the light-emitting diode (LED1) is connected with its cathode (K) to the output of the first half-bridge (HB1: T1, T2) and- wherein the light-emitting diode (LED1) is connected with its anode (A) to the output of the second half-bridge (HB2: T3, T4) and- wherein the first positive supply voltage (VCC1) and the second positive supply voltage (VCC2) can be equal and- wherein the first negative supply voltage (GND1) and the second negative supply voltage (GND2) can be equal and- wherein the light source, in particular the one or more light-emitting diodes (LED1), represents the load of the H-bridge (H) between the output of the first half-bridge (HB1: T1, T2) and the output of the second half-bridge (HB2: T3, T4) and- wherein the control device (ST) is designed to operate in pulsed mode (GPB) a “PAn” condition,in which a forward voltage in the forward direction of the light-emitting diode (LED1) is applied to the light-emitting diode (LED1) through the H-bridge (H), is not maintained by the H-bridge (H) for longer than a turn-on time (τpp), and- wherein the control device (ST) is designed so that in pulsed operation (GPB) a "PAus" state, in which a reverse voltage against the forward direction of the light-emitting diode (LED1) is applied to the light-emitting diode (LED1) through the H-bridge (H), is not maintained by the H-bridge (H) for longer than a clearing time (τpn), and- wherein the clearing time (τpn) is less than the charge carrier lifetime (τ) in the PN junction of the light-emitting diode (LED1), and- wherein the turn-on time (τpp) is less than the charge carrier lifetime (τ) in the PN junction of the light-emitting diode (LED1).

This invention relates to the field of chip technology, specifically to a high-voltage GPP chip with composite trenches and its fabrication method, comprising: N layers arranged sequentially from bottom to top. + Substrate, N-layer, P-layer + Layer, the N + The substrate layer and the N layer form an N-N + Substrate, the P + Layer P and N layers constitute P + -N junction; trenches in the chip edge region, with the inner walls of the trenches covered by a composite passivation layer, the composite passivation layer comprising an inner boron-doped silicon glass layer and an outer phosphorus-doped silicon glass layer; an isolation ring on the inner side of the trench; covering P + Layer surface and N + The metal layer on the lower surface of the substrate serves as the electrode lead-out layer of the chip. The optimized fabrication process of this invention is highly compatible with each structure, achieving a comprehensive improvement in the overall performance of the chip. The matching of each fabrication step with the structural design allows the functions of each component of the chip to be fully utilized, synergistically achieving a comprehensive effect of high breakdown voltage, low leakage current, low forward voltage drop, and excellent high-temperature stability.

The utility model discloses a red lamp pearl voltage drop balance circuit, including commercial power input circuit and transformer circuit, the output of transformer circuit is connected with constant voltage constant current circuit, and the output of constant voltage constant current circuit is parallel with red light lamp pearl control circuit, white light lamp pearl, green light lamp pearl and blue light lamp pearl, still be provided with control drive circuit, control drive circuit is connected with red light lamp pearl control circuit, white light lamp pearl, green light lamp pearl and blue light lamp pearl respectively. The utility model discloses the structure is reasonably set, reduced the use of resistance, is favorable to reduce cost, reduces the waste of power supply, is provided with red light lamp pearl control circuit, and it only needs to separately carry out DC-DC constant current control to red light lamp pearl, can separately adjust and control the forward voltage drop of red light lamp pearl, does not need extra resistance series connection again, can guarantee the illumination of red light lamp pearl under the condition of lower input power, improves the utilization of power supply, can reduce the volume of lamp body.

The application relates to the technical field of LED lamp bead detection, and discloses an LED lamp bead light decay prediction method and system, which comprises the following steps: collecting the luminous flux, junction temperature and forward voltage of an LED lamp bead to obtain LED operation parameter data; performing first-order derivative and second-order derivative calculation on the LED operation parameter data to obtain parameter change rate data; performing composite threshold value detection on luminous flux drop events, temperature jump events and thermal resistance mutation events based on the parameter change rate data to obtain light decay event detection results; and generating lamp bead identification results including a thermal attenuation mode, an electromigration attenuation mode or a photochemical attenuation mode according to the light decay event detection results, in combination with carrier injection efficiency values, fluorescent powder quantum efficiency values and chip defect density values, the application drives physical parameter calculation and mode identification based on event detection results, realizes a technical transformation from passive response to active identification, and significantly improves the real-time performance and accuracy of LED light decay prediction.

The application relates to a high-isolation liquid-crystal-based power-division phase shifter, belonging to the technical field of communication, which comprises a power-division phase-shifting layer, a liquid crystal layer and a bias control layer, an upper ground is arranged above the power-division phase-shifting layer, the liquid crystal layer is arranged below the power-division phase-shifting layer, and a lower ground is arranged between the liquid crystal layer and the bias control layer; the two ends of the power-division phase-shifting layer are respectively connected with an input end and an output end, the bias control layer is connected with a PFGA control, the forward voltage of the bias control layer is fed to the liquid crystal in the liquid crystal layer by being applied to the lower ground, the voltage size of the bias control layer is controlled by the FPGA, then the effective dielectric constant of the bias control liquid crystal is controlled, the capacitance value is changed, then the phase shift constant of the electromagnetic wave is changed, and the phase shift purpose is achieved. The application applies the bias voltage below the microstrip transmission line, not only reduces the wave beam leakage problem caused by the coupling and the direct-current blocking capacitor, but also omits the choke and the direct-current blocking capacitor design, and realizes the miniaturization of the overall structure.

The present application relates to the technical field of semiconductor manufacturing, and particularly relates to a light emitting diode, a light emitting device and a manufacturing method. The light emitting diode comprises an epitaxial structure with a first surface and a second surface, and the epitaxial structure comprises a first semiconductor layer; the first semiconductor layer comprises a first ohmic contact layer on the side of the first surface, which is made of Al x Ga y InP, 0<=x<=1 or 0<=y<=1; a first metal electrode is located on the first surface and comprises a main electrode and a plurality of extension electrodes; the extension electrodes are located on the first ohmic contact layer; the projected area of the extension electrodes on the first surface is less than or equal to the projected area of the first ohmic contact layer on the first surface as viewed from the top. The present application can effectively solve the problem of large light absorption of the traditional GaAs as the ohmic contact layer, avoid the problem of unstable forward voltage output caused by wafer deformation or alignment deviation during the process of the traditional gold half contact, and effectively improve the electrochemical corrosion resistance of the entire electrode structure.

Headlights (SW), in particular for use in vehicles,- with at least one first LED (LED1) as a light source and- wherein the headlight (SW) may include further light sources and- wherein the headlight (SW) emits light in a emitted wavelength range (AWB) in the visible wavelength range and- wherein the headlight (SW) is capable of emitting light pulses in at least one visible wavelength range, the light pulsed wavelength range (LPWB) and- wherein the light pulsed wavelength range (LPWB) is a sub-range of the emitted wavelength range (AWB) of the headlight (SW) or is equal to the emitted wavelength range (AWB) of the headlight (SW) and- wherein the first LED (LED1) can emit light in this light pulsed wavelength range (LPWB) and- with an H-bridge (H) for controlling and supplying the first LED (LED1) with electrical energy,- wherein the H-bridge (H) is controlled by a control device (ST) and- wherein the H-bridge (H) can be operated by the control device (ST) in pulsed mode (GPB) and in quasi-continuous mode (QDB) and- wherein the control device (ST) is designed such that in pulsed mode (GPB) a "PAn" state, in which a forward voltage in the forward direction of the LED (LED1) is applied to the LED (LED1) by the H-bridge (H), is not maintained by the H-bridge (H) for longer than a turn-on time (τpp) and- wherein the control device (ST) is designed such that in pulsed mode (GPB) a "PAus" state, in which a reverse voltage is applied to the LED (LED1) by the H-bridge (H), is not maintained by the H-bridge (H) for longer than a turn-off time (τpn)and- where the clearing time (τpn) is less than the charge carrier lifetime (τ) in the PN junction of the light-emitting diode (LED1) and- where the turn-on time (τpp) is less than the charge carrier lifetime (τ) in the PN junction of the light-emitting diode (LED1).

Headlight (SW), in particular for use in vehicles,- with at least one first LED (LED1) as a light source and- with an H-bridge (H) for controlling and supplying the first LED (LED1) with electrical energy,- wherein the headlight (SW) has a first operating mode (QDB) in which the first LED is used as a light source for illumination purposes and- wherein the headlight (SW) has a second operating mode (GPB) in which the first LED is used as a light source for generating light pulses (LP) in a function as a component of an optical data communication device and- wherein the H-bridge (H) is controlled by a control device (ST) and- wherein the H-bridge (H) can be operated by the control device (ST) in pulsed operation (GPB) in the second operating mode and in quasi-continuous operation (QDB) in the first operating mode and- wherein the control device (ST) is designed tothat in pulsed operation (GPB) a "PAn" state, in which a forward voltage in the forward direction of the light-emitting diode (LED1) is applied to the light-emitting diode (LED1) through the H-bridge (H), is not maintained for longer than a turn-on time (τpp) by the H-bridge (H), and- wherein the control device (ST) is designed such that in pulsed operation (GPB) a "PAus" state, in which a reverse voltage against the forward direction of the light-emitting diode (LED1) is applied to the light-emitting diode (LED1) through the H-bridge (H), is not maintained for longer than a turn-off time (τpn) by the H-bridge (H), and- wherein the turn-off time (τpn) is less than the charge carrier lifetime (τ) in the PN junction of the light-emitting diode (LED1), and- wherein the turn-on time (τpp) is less than the charge carrier lifetime (τ) in the PN junction of the light-emitting diode (LED1) is.,

The present application relates to the technical field of wafer level detection and process tracing of semiconductor light source devices, and particularly relates to a wafer level CSP light source package deviation tracing positioning system, which acquires wafer identification and chip coordinates, collects package deviation and pulse forward voltage of a unit, calculates deviation multi-domain complexity, node temperature transient and drift, fuses into a risk index and controls encrypted sampling and current / duty cycle scanning with double thresholds, generates a hierarchical wafer map with deviation code levels and outputs positioning results combined with process tracing, binds coordinates and voltage deviation data, unifies complexity + thermal drift into a risk index, adaptively encrypts and scans according to double thresholds, and accurately positions by combining a hierarchical wafer map with process tracing.

The application discloses a power tube control circuit of a Buck type LED driver and belongs to the technical field of power electronics. The power tube control circuit comprises a logic control circuit, a charge pump BOOT driving circuit, a dead time circuit and a power tube driving circuit. The logic control circuit is connected with the charge pump BOOT driving circuit and the dead time circuit. The charge pump BOOT driving circuit is connected with the dead time circuit, a charging tube and a freewheeling tube. The dead time circuit is connected with the power tube driving circuit. The power tube driving circuit is connected with the charging tube and the freewheeling tube. The application adopts NMOS tubes to replace traditional bootstrap diodes, eliminates forward voltage drop loss and improves conversion efficiency. The integrated charge pump ensures reliable charging in the full load range. The double dead time circuit realizes precisely adjustable power tube switching delay and completely eliminates the risk of direct-through. All modules can be integrated in a single chip, which simplifies system design and reduces static power consumption.

This application relates to the field of DC power transmission in power systems, specifically to a DC transmission system for offshore wind power via a DR-MMC series topology and its self-starting control method. The method includes: after the receiving-end HMMC establishes a positive DC voltage, it actively adjusts to a preset negative voltage value, causing the DR to naturally conduct due to the positive voltage; while the DR is naturally conducting, power is fed back from the receiving-end grid to the sending-end FBMMC through the receiving-end HMMC to charge the FBMMC and start the wind turbine; the FBMMC and wind turbine automatically switch control modes based on locally detected DC current to achieve autonomous coordination; the receiving-end HMMC restores the DC voltage from a negative value to the positive rated value, during which the DR is activated, and simultaneously the wind turbine increases its power output to the rated value, and the system enters rated rectification operation. Utilizing the negative voltage operation capability of the FBMMC and HMMC, the DR can be automatically activated without the need for additional auxiliary equipment such as bypass switches.

Headlights (SW), in particular for use in vehicles, - with at least one first LED (LED1) as a light source, - wherein the headlight (SW) has a first operating mode (QDB) in which the first LED (LED1) is used as a light source for illumination purposes, and - wherein the headlight (SW) has a second operating mode (GPB) in which the first LED (LED1) is used as a light source for generating light pulses (LP) in a function as a component of an optical measuring device, - with an H-bridge (H) for controlling and supplying the first LED (LED1) with electrical energy, - wherein the H-bridge (H) is controlled by a control device (ST), and - wherein the H-bridge (H) can be operated by the control device (ST) in pulsed operation (GPB) in the second operating mode and in quasi-continuous operation (QDB) in the first operating mode, and - wherein the control device (ST) is designed tothat in pulsed operation (GPB) a "PAn" state, in which a forward voltage in the forward direction of the light-emitting diode (LED1) is applied to the light-emitting diode (LED1) through the H-bridge (H), is not maintained for longer than a turn-on time (τpp) by the H-bridge (H), and- wherein the control device (ST) is designed such that in pulsed operation (GPB) a "PAus" state, in which a reverse voltage against the forward direction of the light-emitting diode (LED1) is applied to the light-emitting diode (LED1) through the H-bridge (H), is not maintained for longer than a turn-off time (τpn) by the H-bridge (H), and- wherein the turn-off time (τpn) is less than the charge carrier lifetime (τ) in the PN junction of the light-emitting diode (LED1), and- wherein the turn-on time (τpp) is less than the charge carrier lifetime (τ) in the PN junction of the light-emitting diode (LED1) is.,

The present invention provides a nitride semiconductor light-emitting element that can lower the forward voltage in a light-emitting element formed by tunnel junction of multiple semiconductor parts that emit ultraviolet light. [Solution] A light-emitting element comprising: a first semiconductor part having a first n-side semiconductor layer, a first active layer disposed on the first n-side semiconductor layer and emitting ultraviolet light, and a first p-side semiconductor layer disposed on the first active layer; and a second semiconductor part having a second n-side semiconductor layer disposed on the first semiconductor part, a second active layer disposed on the second n-side semiconductor layer and emitting ultraviolet light, and a second p-side semiconductor layer disposed on the second active layer, wherein the first p-side semiconductor layer comprises a first layer containing Al and a second layer disposed on the first layer and containing Al and p-type impurities; the second p-side semiconductor layer comprises a third layer containing Al and a fourth layer disposed on the third layer and containing Al and p-type impurities; the second n-side semiconductor layer is tunnel-junctioned with the second layer; and the thickness of the first layer is thinner than the thickness of the third layer.

This invention discloses an apparatus for measuring oxygen saturation. The apparatus includes a circuit system configured to: measure a first diode voltage at a light-emitting diode (LED) when a first current is applied through the LED; measure a second diode voltage at the LED when a second current is applied through the LED; and measure a third diode voltage at the LED when a third current is applied through the LED. The circuit system is further configured to: determine a series resistance based on the first, second, and third diode voltages; and determine the intensity of a received photon signal corresponding to an output photon signal generated using the LED. The circuit system is further configured to determine the oxygen saturation level based on the intensity of the received photon signal and the series resistance.

This invention relates to the field of communication technology and provides a sensor node and communication method for harvesting energy in the idle state of a bus. The hardware includes: a polarity adaptive rectification front-end composed of an ideal diode controller or an ultra-low forward voltage drop Schottky bridge rectifier; an energy storage unit using a large-capacity supercapacitor to store energy in the idle state of the bus; a power management unit including a window voltage monitor, a load switch, and a low-dropout linear regulator; a main control unit: an ultra-low-power MCU with RTC timed wake-up and ADC high-precision voltage monitoring functions; a communication unit with an RS485 half-duplex transceiver with enable control and support for the Modbus-RTU protocol; and a sensing unit consisting of replaceable low-power sensor modules connected to the main control unit via a standardized interface. This device overcomes the technical shortcomings of traditional RS485 sensors, such as high wiring costs, cumbersome maintenance, poor low-temperature reliability, limited node capacity, and insufficient explosion-proof safety.

The present application relates to the technical field of water purification, and provides a water purification device. The water purification device comprises a water purification output pipeline, a waste water output pipeline, a filter core assembly, a power supply assembly and a water path control assembly. The filter core assembly has a water inlet end, a first water outlet end and a second water outlet end. The filter core assembly comprises electrodes, and a first flow channel and a second flow channel are formed between the electrodes. The power supply assembly is used for applying reversible direct current voltage to the electrodes. When the power supply assembly applies a forward voltage, the water path control assembly connects the first water outlet end and the water purification output pipeline, and connects the second water outlet end and the waste water output pipeline. When the power supply assembly applies a reverse voltage, the water path control assembly connects the second water outlet end and the water purification output pipeline, and connects the first water outlet end and the waste water output pipeline. The water purification device of the present application synchronously performs water purification and electrode regeneration in the first flow channel and the second flow channel. Users do not need to wait for the regeneration period, and can obtain continuous water supply at any time.

This invention discloses a vertically double-diffused metal-oxide-semiconductor field-effect transistor and its fabrication method, belonging to the field of semiconductor technology. It includes: a substrate, an epitaxial layer, a base region, a source region, a gate polysilicon, a source polysilicon, a source oxide layer, a gate oxide layer, a shielding oxide layer, a gate metal, a source metal, and a back metal. The gate polysilicon and source polysilicon form a quad polysilicon structure on the front side of the device, including gate polysilicon on both sides and source polysilicon in the middle. In this invention, the thickness of the source oxide layer below the source polysilicon is less than the thickness of the gate oxide layer below the gate polysilicon. Under reverse bias, the source polysilicon is connected to a positive potential, and a conductive channel is induced below the source polysilicon, forming a built-in channel diode structure. The forward voltage of this built-in channel diode structure is much lower than the forward voltage of a conventional MOSFET diode, optimizing the reverse freewheeling characteristics of the device.

This application provides a short-circuit identification method for water pump frequency converters based on the IGBT body diode voltage drop slope, applied to the short-circuit protection system of a water pump frequency converter controller. The method includes: real-time capture of the collector-emitter forward voltage drop signal generated by the lower arm insulated gate bipolar transistor during the inductive load freewheeling phase; continuous discrete voltage sampling at a preset sampling frequency during the effective freewheeling period; obtaining the instantaneous voltage drop change rate between adjacent sampling points through digital differential logic; comparing the absolute value of the instantaneous voltage drop change rate with a preset critical slope threshold and a time window threshold to perform dual determination; and triggering a hardware logic blocking drive signal when a short-circuit fault is detected at the output terminal.

This invention provides a high-precision compensation circuit, method, and device for multiple input voltage channels. It detects the input signal to the MCU processor using at least one first detection circuit, and performs voltage detection and compensation on multiple first detection circuits using a second detection circuit. Based on the voltage difference, it performs differential voltage compensation, achieving consistent control of multiple input voltage channels. Through simple calculations, it eliminates errors caused by temperature variations in diode forward voltage and leakage current of clamping diodes, improving detection accuracy. The compensation circuit, combining the first and second detection circuits, achieves an error of less than 0.05V within an input voltage range of 0~36V.

The display device for a signboard of an embodiment of the present application includes: an LED package having a plurality of LED groups; an illuminance sensor for detecting the illuminance of external light; and a control unit for controlling the LED package according to the illuminance sensor; the plurality of LED groups each have a different forward voltage, and the control unit can drive the LED package in different modes according to the illuminance sensor.

A method for calibrating a spectrometer device (110), wherein the method comprises the following steps: 1) receiving a dependency / 1(U 1) of a radiation intensity / 1 of the first light emitting element (128) of the spectrometer device (110) depending on a first forward voltage U 1 applied for driving the first light emitting element (128); 2) receiving a dependency I 2(U 2) of a radiation intensity I 2 of a second light emitting element (130) of the spectrometer device (110) depending on a second forward voltage U 2 applied for driving the second light emitting element (130); 3) determining the items of calibration information c R (formula I) and c O (formula II) wherein the determined c R and c O are constants with respects to the first forward voltage U 1 and the second forward voltage U 2.

The purpose of this disclosure is to provide a lighting control system and lighting device that can dynamically determine the target voltage before lighting in a voltage conversion circuit and prevent lighting abnormalities of the light source. [Solution] The lighting control system of this disclosure comprises a lighting device and a target voltage determination device. The lighting device performs, at the start of lighting the light source, a first rise process which activates a voltage conversion circuit and raises the output voltage of the voltage conversion circuit to the pre-lighting target voltage, a second rise process which raises the output voltage from the pre-lighting target voltage with the constant current circuit activated, and a process which detects the actual output voltage of the voltage conversion circuit when the current flowing to the light source reaches a preset threshold due to the second rise process. The target voltage determination device determines a new pre-lighting target voltage that matches the forward voltage of the light source based on the actual output voltage. The lighting device performs the first rise process based on the new pre-lighting target voltage when the light source is to be lit again.

This invention relates to a high-voltage ideal diode controller circuit, comprising a controller chip and an external NMOS transistor. The chip integrates a bandgap reference source, an oscillator, a charge pump, a gate comparator, a fast pull-down comparator, a fast pull-down transistor, a clamping diode, and two 25mV reference sources. The gate comparator monitors the voltage difference between the input voltage VIN and the output voltage VOUT in real time, dynamically adjusting the gate voltage to turn on the NMOS transistor. Under light load conditions, the forward voltage difference is controlled at 25mV, significantly reducing power consumption. The fast pull-down comparator is triggered when VOUT is higher than VIN, quickly turning off the NMOS transistor within 500ns to prevent reverse current flow. The controller chip features soft-start, input reverse connection protection, and output clamping functions, with a simple external circuit. This invention is suitable for power supply main backup systems, achieving seamless switching and significantly reducing size and heat dissipation requirements.

This invention provides a composite semiconductor device with low forward voltage drop and a method for driving the same, which can reduce losses during reverse recovery switching. [Solution] A composite semiconductor device comprising: a first diode in which the impurity concentration in the second anode region is higher than that in the first anode region of the first diode; a crystal defect density in the crystal defect region provided within the drift region of the second diode is lower than that in the crystal defect region provided within the drift region of the first diode; and a switch provided to operate the first diode and the second diode at different timings.

The application relates to the technical field of wireless power supply, in particular to a multi-relay wireless power supply system modeling method, which comprises the following steps: S1, constructing a circuit equation based on an impedance matrix according to the circuit topology of the multi-relay wireless power supply system, and performing LDU decomposition on the impedance matrix of the system to obtain a lower triangular impedance matrix, a diagonal impedance matrix and an upper triangular impedance matrix; S2, performing forward voltage transformation according to the lower triangular impedance matrix and a system input voltage phasor; S3, solving forward current according to the diagonal impedance matrix and the forward voltage; S4, performing backward current transformation according to the upper triangular impedance matrix and the forward current to solve loop currents of the multiple relay coils. The method can clearly describe the cross-coupling relationship between the coils of the multi-relay wireless power supply system, can decompose the coil composition of each loop, and can be used for analyzing the input, output and other characteristics of the multi-relay wireless power supply system under complex cross-coupling.

The application discloses a buried P+ SiC JBS structure with improved anti-single-particle performance, which comprises a cathode metal, an anode metal, an SiC N+ substrate, an N-type buffer layer, an N-epitaxial layer, a P+ buried layer and a JBS contact P+, the N-type buffer layer and the N-epitaxial layer are arranged above the SiC N+ substrate, the JBS contact P+ is connected above the N-epitaxial layer, wherein the JBS contact P+ is arranged between the cathode metal and the N-epitaxial layer, the N-type buffer layer is arranged between the N-epitaxial layer and the SiC N+ substrate, the cathode metal is arranged below the SiC N+ substrate, the anode metal is arranged above the JBS contact P+, and the P+ buried layer is arranged between the N-epitaxial layer and the JBS contact P+. The SiC JBS structure is improved, the original SiC JBS structure is ensured to have the advantages of low forward voltage drop and small reverse leakage current, meanwhile, the collection of holes to the anode metal and the collection of electrons to the cathode metal can be reduced during single-particle irradiation, and the excessive leakage and burning are prevented.

The application relates to the technical field of semiconductors, in particular to a resistance test structure, a resistance test method and a semiconductor structure. The resistance test structure comprises a resistance structure to be tested; the resistance structure to be tested comprises metal wires of different types or through holes connecting different metal layers; a preset number of pads, the resistance structure to be tested is located in a circuit between two adjacent pads in the preset number of pads; a diode is located in a circuit between the resistance structure to be tested and a target pad, and the target pad is one of two adjacent thermal pads; wherein the resistance test structure is used to measure the resistance of the metal wires of different types or the resistance of the through holes connecting the different metal layers under the condition that a forward voltage or a negative voltage is applied to the diode. The application can test the resistance of the metal wires of different types or the through holes connecting the different metal layers by multiplexing the preset number of test pads, thereby reducing the consumption of pad resources and wafer area.

The application discloses an auxiliary power supply circuit of a forward switching power supply, which comprises an input voltage Vin, a transformer T1, a main switch tube Q1, a diode D2, a diode D3, an inductor L1-1, a capacitor C2, an output voltage Vo and a load, and the transformer T1 comprises a primary winding, a secondary winding and an auxiliary winding Nf; the auxiliary power supply circuit further comprises an inductor L1-2, a diode D1, a capacitor C1 and a PWM chip; when the main switch tube Q1 is turned on, the auxiliary winding Nf forward voltage minus the inductive voltage of the inductor L1-2 is equal to a stable voltage, which is used as an auxiliary voltage for supplying the PWM chip; the auxiliary power supply circuit has the advantages of simple circuit, high efficiency and stable Vcc voltage in the whole working range; meanwhile, the auxiliary winding Nf is directly connected with the inductor L1-2 without other elements connected in between, so that when the multi-layer PCB board is wired, the inner layer is directly connected, and the insulation pressure resistance is easy to realize.

In an embodiment, a semiconductor device includes: a main bi-directional switch formed on a semiconductor substrate and including first and second gates, a first source electrically connected to a first voltage terminal, a second source electrically connected to a second voltage terminal, and a common drain; and a substrate control circuit. The substrate control circuit includes: a first diode and a second diode; a discharge circuit including a first transistor and a second transistor connected in a common source configuration to the semiconductor substrate; and a gate potential control circuit including a third diode and a fourth diode. The first diode has a forward voltage Vf1 and the third diode has a forward voltage Vf3, where Vf1≥1.1Vf4 or Vf1≥1.2Vf4 or Vf1≥1.5Vf4 or Vf1≥2Vf4.