30results about How to "Few external components" patented technology

The present invention relates to a constant current and voltage controller carrying out pin multiplexing and a three-pin package for carrying out low-cost flyback converters. A flyback converter includes a controller integrated circuit (IC) housed in an IC package with only three terminals. An inexpensive TO-92 transistor package can be used. A switch terminal is coupled to an inductor switch that is turned on by a switch control signal having a frequency and a pulse width. The inductor switch controls the current that flows through a primary inductor of the flyback converter. The controller IC adjusts the frequency in a constant current mode such that output current remains constant and adjusts the pulse width in a constant voltage mode such that output voltage remains constant. A power terminal receives a feedback signal that is derived from a voltage across an auxiliary inductor of the flyback converter. The feedback signal provides power to the controller IC and is also used to generate the switch control signal. The controller IC is grounded through a ground terminal.

The invention discloses a radiofrequency power detection circuit. A resistor R1, a resistor R2, a resistor R3 and a first diode are orderly and serially connected between a power end VCC and the ground, a signal input end RFIN is connected to a node between the resistor R2 and the resistor R3 through a capacitor C1, the node is also connected with a base electrode of a triode Q2, a collector of the triode Q2 is connected to a node between the resistor R1 and the resistor R2, a second diode and a resistor R4 are orderly and serially connected between an emitter of the triode Q2 and the ground, a resistor R5 and a resistor R7 are orderly and serially connected between the emitter of the triode Q2 and a signal output end VOUT, a capacitor C2 is connected between a node (between the resistor R7 and the resistor R5) and the ground, and a resistor RL is connected between the signal output end VOUT and the ground. The radiofrequency power detection circuit sets a direct current operating point of a radiofrequency power detector, eliminates the limit of positive voltage of a rectifier diode, and increases the range of radiofrequency power detection; and the detection circuit can be integrated into an HBT power amplification chip, which reduces peripheral elements of a power amplifier and saves the area of a printed circuit board.

The invention provides a flyback power converter, which comprises a transformer, a first rectifier, a second rectifier, a first capacitor, a second capacitor, a first resistor, a second resistor, a third resistor, a fourth resistor, a switch transistor and a pulse frequency modulation and a pulse width modulation controller, wherein the pulse frequency modulation and a pulse width modulation controller is used for providing a control signal to drive the grid of the switch transistor; the transformer comprises a primary winding, a secondary winding and an auxiliary winding; one end of the primary winding is connected with the power supply input end of the flyback power converter, and the other end of the primary winding is connected with the drain of the switch transistor; the switch transistor is used for controlling the voltage of the primary winding; one end of the secondary winding is grounded, and the other end of secondary winding is connected with the anode of the secondary rectifier; and one end of the auxiliary winding is grounded, and the other end of the auxiliary winding is connected with one end of the secondary resistor. The structure of the flayback power converter can be effectively simplified.

The invention relates to a leakage monitoring chip for a leakage protector. The leakage monitoring chip comprises a power voltage regulator circuit, a reference voltage generator and a latching output circuit, wherein the power voltage regulator circuit is used for providing working voltage for the reference voltage generator and the latching output circuit; the leakage monitoring chip further comprises a circuit structure and a first amplifying circuit and a second amplifying circuit which have the same performance; an input end of a first differential amplifier circuit is electrically connected with an input end of a second differential amplifier circuit, and the end is used as the public input end to connect with an external circuit; the other input end of the first differential amplifier circuit is connected with the external circuit; the other input end of the second differential amplifier circuit is connected with the external circuit; the output end of the first amplifying circuit and the output end of the second amplifying circuit are electrically connected with the input end of the latching output circuit respectively; the reference voltage generator circuit is used for respectively providing reference voltage for the input ends of the first differential amplifier circuit and the second differential amplifier circuit. The leakage monitoring chip provided by the invention has the advantages that the leakage faults of the main loop and the ground wire can be monitored synchronously; and the two fault action current can be adjusted randomly in the scope of national safety standards; the leakage monitoring chip works stably and reliably and the personal safety can be more effectively protected.

The invention belongs to the technical field of electronics and audio amplification, and relates to a hearing-aid made of a TDA2822 (Tunnel Diode Amplifier). The hearing-aid comprises a direct current (DC) power supply, a power supply filter circuit, a constant current source and pickup circuit, an emitter follower, an audio signal regulating circuit and an integrated power amplification circuit. The hearing-aid is characterized in that the constant current source and pickup circuit is used as a power supply of a capacitor microphone (MIC), the emitter follower is used as a high-resistance amplification circuit, and the type of the integrated power amplification circuit (IC1) in a BTL (Bridge-Tied-load) mode application circuit is TDA2822M. The hearing-aid provided by the invention is formed by combining discrete components and the integrated power amplification circuit. The hearing-aid has the characteristics of simple circuit structure, fewer peripheral elements, little cross distortion, good tone quality, wide working voltage range, less static current and electricity consumption, output power capable of meeting the requirements on people with poor hearing, and the like, and is a hearing-aid attractive in price and quality, thereby solving or overcoming the problems of partial defects existing in some hearing-aids on the market, and the like.

The invention discloses an output-power-adjustable direct-current inverter. The direct-current inverter consists of a 12V direct-current power supply, a multi-vibrator circuit, a pulse width modulating circuit, a voltage comparison circuit, a push-pull power amplifying circuit, a booster circuit and a rectangular wave voltage shaping circuit, and is characterized in that the model of a pulse width modulation oscillation circuit IC1 in the multi-vibrator circuit is SG3524. The direct-current inverter is a standby power supply which is independent of a commercial power grid. The output-power-adjustable direct-current inverter disclosed by the invention is suitable for equipment such as general illuminating equipment, computers and electronic instruments, can be taken as a temporary emergency power supply for use during short-time power failure of a power supply circuit, and is suitable for emergency illumination or fire-fighting emergency power supplies at various public places. The output-power-adjustable direct-current inverter has the characteristics of simple circuit structure, small quantity of peripheral elements, high conversion efficiency, small temperature rise in a rated power range, output power being up to 400W, and adjustability of the output power of the inverter by modulating the pulse width through an external potentiometer.

A generator voltage regulator for constant-frequency trigger excitation, comprising: a transistor array integrated chip 3, including four crystal groups, respectively used to form a fixed-frequency oscillation circuit, a pulse shaping circuit, and a power trigger circuit; a fixed-frequency oscillation resistance-capacitance circuit The component part 2 forms a fixed-frequency oscillation circuit with two crystal groups; the power unit 5, the feedback unit 6, and the feedback unit is connected to the output terminal of the power unit and the input terminal of the third crystal group to form a power trigger circuit; the freewheeling unit 7, Used to provide a continuous current path; the sampling unit 1 is used to sample the output voltage; the threshold unit 4 is connected to the sampling unit and the third crystal group to provide a reference value; the output terminal of the fixed frequency oscillation circuit is connected to the fourth crystal through a capacitor The group input terminals are connected to form a pulse shaping circuit, and the fixed frequency triggers the power trigger circuit to set it to turn on the excitation current. When the output voltage of the generator is greater than the set value, the sampling voltage triggers the power trigger circuit through the threshold unit to reset and cut off the excitation. current.

The invention discloses a high-integration control chip and a power supply circuit with the same. The high-integration control chip comprises a switching tube, a driving module, a primary constant-voltage control module and a slope compensation module. The primary constant-voltage control module is connected with a primary side voltage feedback end of a switching power supply and the driving module, and constant-voltage control processing is carried out on feedback voltage of the primary side voltage feedback end of the switching power supply. The slope compensation module is respectively connected with the primary side voltage feedback end of the switching power supply and the primary constant voltage control module. Slope compensation processing of the output voltage is carried out according to the primary side voltage feedback value, so that the switching power supply circuit outputs a voltage value with a set slope. Therefore, the voltage and current slope requirements of battery charging and motor driving can be met. The power supply circuit adopts a primary side feedback mode, so that peripheral circuits such as feedback optocouplers can be reduced, and peripheral elements ofthe circuit are reduced.

The invention discloses a wireless endoscope system with a multipoint networking function, and relates to the technical field of medical instruments, the wireless endoscope system comprises a wireless endoscope host, a wireless receiving end, a display device and an intelligent control device, the wireless endoscope host comprises a detachable cold light source and a wireless RF radio frequency transmission module, the wireless endoscope host supplies power to the detachable cold light source, the detachable cold light source provides illumination for the whole wireless endoscope host, the wireless endoscope host is connected with the wireless receiving end through the wireless RF transmission module, the wireless receiving end is connected with the intelligent control device through a signal line, and the intelligent control device is connected with the detachable cold light source. The wireless receiving end is connected with a plurality of intelligent control devices through wifi signals. According to the wireless endoscope system, control and adjustment signals for functional parameters and the like of the wireless endoscope host can be sent, the high-speed local area network networking technology is achieved, the wireless endoscope system can be intelligentized, and doctors can watch operation pictures and function operation of endoscope equipment conveniently.