34results about How to "Enhanced overcurrent protection" patented technology

A lighting circuit for a light source includes a drive circuit and an overcurrent protection circuit. The drive circuit supplies power to the light source. The overcurrent protection circuit is inserted between the drive circuit and the light source. The overcurrent protection circuit restricts a lamp current flowing into the light source so that the lamp current does not exceed an overcurrent threshold value. The overcurrent protection circuit includes a transistor, an inductor, a rectifier, a current sensor and an overcurrent protection controller. The current sensor generates a current detection signal according to the lamp current. The overcurrent protection controller controls ON/OFF of the transistor based on the current detection signal and the overcurrent threshold value. The transistor, the inductor and the rectifier are disposed in a T-shape.

The invention discloses a backlight drive circuit, a driving method thereof and a liquid crystal device. The backlight drive circuit comprises a power module and a constant current driving chip, the power module comprises a first controllable switch, an adjustable load is connected between the first controllable switch and a backlight drive circuit grounding end, the adjustable load comprises a switching module capable of switching different resistance values, a control end of the switching module is coupled to a mode switch signal of the backlight drive circuit, and one end of the adjustable load, which is connected with the first controllable switch, is coupled to an over-current protection port of the constant current driving chip. According to the backlight drive circuit, the driving method thereof and the liquid crystal device, two and even more over-current protection (OCP) threshold values can be provided, and reliable over-current protection can be achieved whether in a 2 dimensional (2D) or 3 dimensional (3D) mode.

An overcurrent detection circuit (35) that detects an overcurrent state of a transistor (2) that outputs a current to a load (25) is provided with a start-up monitoring portion (31) that distinguishes between a start-up state and a steady state, an overcurrent monitoring portion (33) that monitors an overcurrent state of the transistor (2), and an output voltage monitoring portion (34) that detects whether the output voltage to the load (25) is normal or abnormal. The overcurrent monitoring portion (31) changes an overcurrent detection level while referring to information from the start-up monitoring portion (31) and the overcurrent monitoring portion (33).

The embodiment of the invention provides an overcurrent protection device and method for an inverter as well as the inverter, which relate to the electrical and electronic field. The overcurrent protection device and method as well as the inverter are invented for efficiently improving overcurrent protection for the inverter at lower cost. The inverter comprises a power alternating circuit, a filtering circuit and the overcurrent protection device, and a change on output voltage of the filtering circuit exceeds the change on inductance current of the filtering circuit; and the overcurrent protection device comprises the following of: a voltage sampling unit which is used for sampling output voltage of the filtering circuit; a voltage comparison unit which is used for comparing the sampling output voltage sampled by the voltage sampling unit with preset voltage; and a current-limiting unit which is used for limiting current for the power alternating circuit when output voltage of the filtering circuit is reversed with theoretical output voltage and an absolute value of output voltage of the filtering circuit is larger than that of preset voltage. The overcurrent protection device and method for inverter as well as the inverter can be applied in a contravariant power supply.

The invention belongs to the technical field of compressor control, and provides an air conditioner compressor protection and control method and device. According to the method, when an over-current detection signal is received at a protection signal input end of an intelligent power module, whether a fault signal is output at a fault signal output end of the intelligent power module in a preset period of time or not is judged; if yes, a power source protection switch module is controlled to output power supply currents in a direct power supplying mode; otherwise, it shows that the intelligent power module is damaged, and therefore the power source protection switch module needs to be controlled to reduce the power supply currents in a current-limiting mode to a preset safety current range. Thus, on the condition that the intelligent power module is damaged, the abnormal over-current phenomenon is prevented from occurring in driving currents of an air conditioner compressor by reducing the power supply currents, a good over-current protection effect is achieved on the air conditioner compressor and the problem that in the prior art, when an intelligent power module is damaged, over-current protection of an air conditioner compressor cannot be realized is solved.

The invention discloses a power electronic reactor performance test device, which comprises a soft start module, an LCL filter module, a rectifier module, an energy storage module, an inverter module, a measurement module and a control unit module connected in sequence, wherein the input end of the soft start module is connected with an external power supply; the output end of the inverter module is connected with a tested reactor; the measurement module, the soft start module and the inverter module are connected with the control unit module respectively; the measurement module feeds sensor information back to the control unit module; and the control unit module controls the soft start module and drives the inverter module. The test device can simulate different working conditions, temperature rise test on the reactor is completed, on-load switching among test modules can be realized, shut down is not needed, the test work continuity is ensured, the time is saved, the working efficiency is improved, the test device is convenient to operate, and the device has the advantages that the power loss is little; the power is saved; a backstage can be connected in an online mode; and the test data can be transmitted in real time.

The invention discloses an LED drive circuit and method based on voltage memory and segmented current limiting. The circuit comprises a rectifying circuit, a voltage division circuit, a voltage increasing and reducing detection module, a voltage memory module, a comparator set, a control logic module, a high-voltage switch circuit, a detection resistor, a current detection comparator and an LED lamp string. According to the drive method of the circuit, according to the increasing and reducing characteristics of the directly-rectified direct-current ripple voltages, the segmented type lightening control mode is adopted in the load of the LED lamp string. The drive circuit solves the problem of the influence of the difference of voltage current characteristics of an LED chip adopted by the lamp string in the actual application on drive currents, the work current of the LED lamp string in the whole work period is limited within the designed largest current value Imax, the problems of lower brightness caused by undercurrents and damage, caused by overcurrents, to the LED chip are solved, the light-emitting efficiency of the LED lamp is improved, and meanwhile overcurrent protection can be carried out on an LED device well.

The invention provides a pre-charging control device for a motor controller of an electric vehicle. The device comprises a power supply switch k1 and a pre-charging module, wherein one end of the power supply switch k1 is connected to the positive pole of the storage battery E1 of the electric vehicle, and the other end of the power supply switch k1 is connected to the positive pole of the capacitor bank Cz of the motor controller; the power supply switch k1 is used for controlling the on/off of the power supply loop of the motor controller; the pre-charging module is connected in parallel with the power supply switch k1 and is used for controlling the pre-charging state of the capacitor bank Cz of the motor controller. According to the pre-charging module, the phenomenon that the capacitor bank is always in a saturated state can be effectively avoided; the pre-charging control device has the overcurrent protection function, thus the capacitor bank is protected, and the service life of the capacitor bank is prolonged, so that the operating reliability of the motor controller is guaranteed, the electric quantity of the storage battery is not consumed by the pre-charging module, the travel distance of the electric vehicle can be prolonged, and a good energy-saving function is realized; and the pre-charging control device is simple in structure, low in manufacturing cost and easy to implement and popularize.

The invention discloses an electric control device of an engine extinguisher. The engine extinguisher comprises a flexible shaft, a motor used for driving the flexible shaft to stretch out and retract back and a detection switch which is turned on or turned off through triggering of the stretching operation and the retraction operation of the flexible shaft. The electric control device comprises a power circuit, a main controller, a first signal processing circuit, a second signal processing circuit, a motor driving circuit and a current sampling circuit used for sampling a driving current of the motor. The input end of the first signal processing circuit is connected with the signal output end of an ignition switch. The input end of the second signal processing circuit is connected with the signal output end of the detection switch. The input end of the main controller is respectively connected with the output end of the first signal processing circuit, the output end of the second signal processing circuit and the output end of the current sampling circuit and the output end of the main controller is connected with the input end of the motor driving circuit. The invention further discloses a control method of the engine extinguisher. According to the electric control device of the engine extinguisher and the control method of the engine extinguisher, the current overcurrent protection function and the self-recovery function when the current is abnormal are achieved and in addition, a motor driving current does not flow across the detection switch.

The invention discloses an overcurrent protection circuit and a driving circuit of a display panel. The overcurrent protection circuit comprises a first control module, a second control module, a detection branch, a first detection module and a second detection module, one end of the detection branch is connected between the first control module and the second control module, and the other end is connected to the input ends of the first detection module and the second detection module; the current on the detection branch is the current to be detected, and when the first detection module detects that the current to be detected is smaller than a preset first threshold value, the second control module is controlled to be switched off to disconnect the load end; and when the second detection module detects that the current to be detected is greater than a preset second threshold value, the first control module is controlled to be switched off, and the power supply end is switched off. According to the over-current protection circuit, the problem that large current occurs at any one of the power supply end or the load end is solved, and the whole driving circuit can be turned off through the over-current protection circuit, so that over-current protection is realized.

The invention provides a server VR chip OCP point setting method and a control circuit, which are used when N loads are configured at the rear end of a server VR chip, can dynamically adjust the OCP points of the server VR chip according to in-place signals of the loads at the rear end of the server VR chip, and specifically comprises the following steps: configuring a resistor access circuit foreach of the N loads, wherein each resistor access circuit comprises a setting resistor accessed between the OCP pin of the server VR chip and the ground and a switch control circuit for controlling the conduction and disconnection of the circuit where the setting resistor is located, and the control end of the switch control circuit of each resistor access circuit is connected with an in-place signal of a corresponding load. The method and the circuit are used for improving the overcurrent protection of the server circuit.

The invention provides a linear direct-current power source comprising a voltage regulator and a power supply management circuit. The power source is characterized by further comprising an output adjustment circuit, an over-current protection circuit and an over-voltage protection circuit, the power supply management circuit comprises a transformer, three taps are arranged at the output end of the transformer and include the tap A, the tap C and the tap B in the middle, the alternating current output by the tap A and the tap C outputs first direct current through full-wave rectification to supply power to the voltage regulator, and the alternating current output by the tap B outputs second direct current through half-wave rectification to supply power to the output adjustment circuit. The overall efficiency of the power source is improved through the middle tap of the transformer, the loading capacity of the power source is improved by additionally arranging a transistor, a high-performance control chip LM723 serves as the kernel, output precision and stability are ensured, and over-current protection and over-voltage protection are achieved; all the circuits are composed of hardware, and the power source is simple in structure, easy to obtain, very high in reliability and maintainability and particularly suitable for being used in application occasions where low-voltage large-current power sources are used.