164 results about "Voltage divider" patented technology

This invention relates to the field of integrated circuit I / O interface design technology. It discloses a dual-mode (digital-analog) input / output interface circuit based on low-voltage devices adapting to high-voltage power supplies, aiming to solve the problems of low-voltage process chips being unable to directly adapt to high-voltage power supplies and limited I / O functionality. The interface circuit includes a digital output module, a digital input module, an analog I / O module, and a mode summary and ESD circuit. Through external configuration signals, the circuit can switch between digital input, digital output, analog I / O, and power-down modes. The digital output module incorporates a dual-mode high-voltage adaptation mechanism, utilizing a voltage divider resistor series and a common-gate protection transistor to ensure the safety of low-voltage devices under high voltage. The digital input module employs non-overlapping control to eliminate dynamic power consumption. A full-mode high-impedance isolation design ensures the reliability of mode switching. This invention achieves safe adaptation of standard low-voltage CMOS devices to high-voltage power supplies and integrates dual-mode functionality, offering advantages such as high integration, low power consumption, high reliability, and strong process compatibility.

This application discloses an MCU sleep / wake-up circuit, including a signal circuit, a second sleep control transistor Q2, a first hierarchical sleep control transistor Q1, an LDO chip U, and a control unit MCU. The signal circuit outputs a wake-up signal. The base of the second sleep control transistor Q2 is connected to the output terminal of the signal circuit through a current-limiting resistor R4, grounded through a voltage divider resistor R9, and connected to the enable terminal ENA through a current-limiting resistor R3. The enable terminal ENA is connected to the control unit MCU, the emitter is grounded, and the collector outputs a control signal. The control signal is input to the first hierarchical sleep control transistor Q1 through a bias voltage divider circuit. The emitter of the first sleep control transistor Q1 is connected to the power supply VIN, and the collector outputs the power supply voltage to the LDO chip U. The LDO chip U outputs its operating voltage to the control unit MCU. When the control unit MCU is working, it outputs a high level to the enable terminal ENA. This application can reduce the complexity of the sleep / wake-up system and achieve low-power sleep and reliable wake-up of the control unit MCU.

This invention discloses a high-voltage capacitor safety discharge device and method, relating to the field of safety discharge technology. The device includes a discharge box, a resistor box, and a control box. The top of the discharge box is equipped with a test electrode for connection to the component to be discharged. Inside the discharge box are at least two robotic arm modules and a voltage divider for monitoring the voltage of the component to be discharged. A conductive electrode is located at the end of each robotic arm module facing the test electrode. The resistor box contains at least two sets of discharge resistors with different resistance values ​​and a temperature sensor. The input terminal of each discharge resistor is connected to a corresponding conductive electrode, and the output terminals of each discharge resistor are connected in series with a current sensor and then grounded. The control box is configured to control at least one robotic arm module to move towards or away from the test electrode based on signals output from the voltage divider, current sensor, and temperature sensor, thereby controlling at least one conductive electrode to contact or disconnect from the test electrode. This invention can improve safety during the discharge process.

This utility model discloses a high-voltage protection control circuit, including a first connector CN1 and a second connector CN2. Between the first connector CN1 and the second connector CN2, there are also: a second Zener diode D2, a first Zener diode D1, a second transistor Q2, a first transistor Q1, a switching transistor Q3, a voltage divider resistor R8, and a step-down chip U1. This utility model utilizes the second Zener diode D2 and the first Zener diode D1 to implement the avalanche effect, directly driving the second transistor Q2 and the first transistor Q1, and delaying overvoltage response, resulting in a significant improvement in response speed. Furthermore, the combination of the second Zener diode D2, the first Zener diode D1, the second transistor Q2, the first transistor Q1, and the switching transistor Q3 implements a complete protection function, reducing the overall circuit area and achieving high circuit integration. Moreover, it eliminates the need for a dedicated IC chip for control, reducing production costs.

This utility model discloses a photovoltaic panel access detection circuit and device. The photovoltaic panel access detection circuit, connected between the photovoltaic panel and the rechargeable battery, includes a low-side switch module, a first voltage divider resistor R1, a second voltage divider resistor R2, and a protection module. The first terminal of the low-side switch module is connected to the negative input terminal of the photovoltaic panel and the first terminal of the second voltage divider resistor R2. The second terminal of the low-side switch module is connected to the negative terminal of the rechargeable battery. The second terminal of the second voltage divider resistor R2 is connected to the first terminal of the first voltage divider resistor R1 and the protection module. The second terminal of the first voltage divider resistor R1 is connected to the positive input terminal of the photovoltaic panel and the positive terminal of the rechargeable battery. This utility model, using components such as a low-side switch, voltage divider resistors, and a protection module, provides a highly efficient and reliable photovoltaic panel access detection circuit. It can not only monitor the input voltage of the photovoltaic panel but also automatically protect the battery and circuit through a clamping protection mechanism when the voltage is too high, ensuring the safe and stable operation of the entire system.

This invention relates to a circuit board for an ozone generator with frequency tracking functionality. The circuit board includes a frequency tracking circuit comprising an RC oscillation unit, an LC resonant unit, a current sampling unit, a comparison control unit, a voltage divider bias unit, and a frequency limiting protection unit. The LC resonant unit includes a resonant inductor T1 and a resonant capacitor C1, used to drive the ozone sensor. The current sampling unit includes a sampling resistor R8 connected in series in the LC resonant circuit, used to acquire the circuit current signal. The comparison control unit includes a comparator U1, a transistor Q1, a rectifier diode D2, and a filter capacitor C3. The voltage signal from the sampling resistor R8 is rectified by D2 and filtered by C3 before being input to the inverting input of U1. The voltage divider bias unit includes resistors R3 and R6. The RC oscillation unit is connected to the transistor Q1. This invention can adapt to capacitance changes during ozone sensor power-on and operation, automatically tracking the frequency and achieving resonance, while ensuring stable output power, extending device lifespan, and improving ozone generation efficiency and overall reliability.

Electric vehicle charging cable (1) for connecting a charging station and an electric vehicle according to the Type 2 standard as defined in IEC 62196-2, comprising: - at least three power lines (2a, 2b, 2c) for three-phase power transmission, - a neutral conductor (3), - a protective conductor (4), - a control pilot signal line (5) as defined in IEC 61851-1, - a proximity pilot signal line (6), - a Type 2 connector (7a, 7b) at each end, characterized in that: - an electronic unit (10) is integrated into the cable or into at least one of the connectors (7a, 7b), - the electronic unit (10) comprises a microcontroller (11) with an analog-to-digital converter, - the microcontroller (11) is connected to the control pilot signal line (5) via a voltage divider (12) and continuously monitors the voltage of this line, - the electronic unit (10) includes at least one acoustic signal generator (13) includes,- the microcontroller (11) is programmed,to distinguish the voltage states of the control pilot line (5) according to IEC 61851-1 (State A: +12 V; State B: +9 V; State C: +6 V; State E: 0 V),- the electronic unit (10) emits a first acoustic signal when transitioning from State A to State B,- the electronic unit (10) emits a second acoustic signal, distinguishable from the first acoustic signal, when transitioning from State B to State C,- the electronic unit (10) emits a third, warning acoustic signal if State B persists for a predefined period of 5 to 15 seconds without transitioning to State C.

This invention provides a power-on detection circuit and a chip. An enable control circuit is added before the voltage divider circuit. During chip power-on, the enable control circuit outputs an enable control signal to enable the voltage divider circuit only after the power supply voltage reaches a first threshold. This avoids the problem of misjudgment by the comparator circuit due to the voltage divider circuit's voltage division establishment speed being equal to or faster than the reference voltage establishment speed. Thus, during chip power-on, problems such as the chip failing to start normally or irreversible damage caused by the output of the power-on detection circuit being incorrectly flipped can be avoided, thereby improving the chip's power-on safety and operational reliability.

The utility model discloses a kind of high-end ideal diode based on band gap reference, including high-end load switch MOS tube, voltage comparator and band gap reference voltage module, the high-end load switch MOS tube, voltage comparator and band gap reference voltage module composition integral circuit, the MOS tube is PMOS tube or NMOS tube.This circuit has the function of preventing backflow, can protect front-stage circuit;With lower loss, small static current loss;Use high-end load switch and voltage comparator, circuit is simple, cost is very low, and practicality is strong;Voltage comparator is used to compare the voltage of the voltage divider of MOS tube output end and reference voltage, band gap reference voltage source has higher precision, strong anti-interference ability, and there is no backflow current;Reduce the static loss of equipment, prolong the working time of battery, equipment maintenance cost is low, loss reduces greatly, suitable for thing networking NB-IoT ultra-low loss ideal diode circuit application, circuit is very simple and has very low cost advantage.

This utility model discloses a motor overcurrent protection device, which includes an overcurrent resistor, an amplifier, a comparator, a logic gate, and a switch. The overcurrent resistor is electrically connected to a control circuit of a motor to obtain a voltage divider signal from the control circuit. The amplifier is electrically connected to the overcurrent resistor and is used to amplify the voltage divider signal. The comparator is electrically connected to the amplifier and the control circuit and is used to compare the amplified voltage divider signal with a signal threshold stored in the control circuit to output a comparison result signal. The logic gate is electrically connected to the comparator and is used to receive the comparison result signal to output a drive signal. The switch is electrically connected to the logic gate and is used to receive the drive signal to cut off the power supply to the motor.

The application relates to a partial discharge coupling device, which comprises a measuring resistor, a parallel inductor, a measuring capacitor, an overvoltage protector P1, an overvoltage protector P2, a partial discharge pulse output end, an AC test voltage output end and a grounding end; the measuring resistor is connected in series with the measuring capacitor, and the grounding end is connected to the measuring capacitor; the parallel inductor is connected in parallel with the measuring resistor, and the partial discharge pulse output end and the AC test voltage output end are connected to two ends of the parallel inductor; the overvoltage protector P1 is connected in parallel with the measuring resistor and the measuring capacitor; the first end of the overvoltage protector P2 is connected between the second end of the parallel inductor and the AC test voltage output end, and the second end of the overvoltage protector P2 is connected between the second end of the measuring capacitor and the grounding end. Compared with the prior art, the application has the advantages of integration, convenient use and the like, realizes the coupling device for completely separating the partial discharge pulse and the test voltage, avoids the need of installing a high-voltage voltage divider in the traditional test loop, and has the advantages of small size and low cost.

This utility model discloses a touch signal conversion and reading circuit, including an MCU. The PWM signal output terminal of the MCU is connected to the MCU's ADC signal detection terminal via resistor R1, capacitor C1, and resistor R2 in sequence. A touch electrode A1 is also connected between capacitor C1 and resistor R2. The MCU's ADC signal detection terminal is equipped with a signal processing module, which includes a resistor R3 and a capacitor C2 connected in parallel. One end of each resistor R3 and capacitor C2 is connected to the MCU's ADC signal detection terminal, and the other end is connected and grounded. This utility model replaces a dedicated chip with "capacitive coupling waveform distortion detection" and combines a hardware hardening design of "diode reverse protection + voltage divider filtering," reducing hardware costs and improving reliability and compatibility.

Vehicle electrical power storage device installed in a vehicle having a vehicle power supply as a power source, wherein the vehicle power supply includes a high-voltage battery (3), and the vehicle electrical power storage device (15) comprises: a control unit (6) that performs internal control of the vehicle electrical power storage device (15); a load (7) that is connected to the high-voltage battery (3) based on a command from the control unit (6) and forcibly consumes power stored in the high-voltage battery (3);and a cooling device (10) which is operated based on a command from the control unit (6) and cools the high-voltage battery (3), and a voltage divider unit (11) which is arranged between the high-voltage battery (3) and the cooling device (10), wherein, when a collision of the vehicle is detected, the control unit (6) forcibly consumes the current in the high-voltage battery (3) using the load (7), connects the high-voltage battery (3) and the cooling device (10) via the voltage divider unit (11), divides the voltage of the high-voltage battery (3) using the voltage divider unit (11), applies the divided voltage to the cooling device (10) and cools the high-voltage battery (3) using the cooling device (10).

The utility model belongs to switching power supply technical field especially relates to a kind of capacitor discharge circuit.This kind of capacitor discharge circuit, by improving discharge topology structure, improve the capacitor discharge efficiency, realized to discharge whole process real-time monitoring and dynamic adjustment, with good market prospect.A kind of capacitor discharge circuit, including have: voltage divider circuit, detection circuit, discharge circuit and main control unit;Voltage divider circuit is formed by the multiple voltage divider resistors of series arrangement;Discharge circuit is formed by main discharge module and assist discharge module;Wherein, main discharge module is formed by the power switch tube and sampling resistance of series arrangement, assist discharge module is formed by the multiple assist discharge resistors of parallel arrangement;Detection circuit includes voltage detection module, current detection module and temperature monitoring module;Main control unit is connected with voltage detection module, current detection module and temperature monitoring module in detection circuit respectively communication.

This invention discloses a fast load-response DC-DC boost converter and a power management system. The DC-DC boost converter includes a DC input voltage source V. IN Switches S1 through S5, inductor L, output capacitor C O Output current source I O and flying capacitor C F The invention includes a control subsystem, a drive subsystem, and the DC-DC boost converter. The control subsystem includes voltage divider resistors, a Type-II compensation network based on an error amplifier, a clock and ramp generation circuit, a comparator, an RS latch, dead time, and drive logic circuitry. The drive subsystem includes a switch driver. This invention features fast load response, a wide voltage conversion ratio, and high efficiency.

A power converter converts a medium-voltage output from a solar module to an appropriate voltage to power a solar tracker system. The power converter includes a voltage divider having at least two legs, a first semiconductor switch subassembly coupled in parallel with a first leg of the voltage divider, and a second semiconductor switch subassembly coupled in parallel with a second leg of the voltage divider. The power converter may be a unidirectional or a bidirectional power converter. In implementations, the signals for driving the semiconductor switches of the first and second semiconductor switch subassemblies may be shifted out of phase from each other. In implementations, if the bus voltages to the semiconductor switches are not balanced, the pulse width of the driving signal of the semiconductor switch supplied with the higher bus voltage is decreased for at least one cycle. 20 25 20 05 53 28 J an 2 02 5 A B S T R A C T 2 0 2 5 2 0 0 5 5 3 2 8 J a n 2 0 2 5

In a capacitive voltage transformer, a shield that holds the voltage divider electrodes in place restricts their elongation in the direction of the inner electrodes. Therefore, output voltage variations caused by thermal deformation of the voltage divider electrodes are less likely to occur, resulting in a more accurate output voltage and achieving high measurement precision or low specific error. Furthermore, the shield, which is attached to the frame, can also undergo thermal deformation, such as elongation in the direction of the inner electrodes. In this case, a force is applied from the shield to the voltage divider electrodes along the direction of the inner electrodes to further suppress elongation in this direction.

This invention relates to a high-voltage, capacitor-free, low-noise linear regulator. It comprises a high-voltage switching voltage follower, a self-zeroing error amplifier, and voltage divider resistors. The high-voltage switching voltage follower significantly enhances the system's transient response to load changes and improves power supply rejection in the mid-frequency range. The self-zeroing error amplifier, together with the high-voltage switching voltage follower, forms a global slow loop. The self-zeroing error amplifier employs a ping-pong self-zeroing method, effectively reducing low-frequency flicker noise and offset while ensuring continuous operation in the time domain. This invention introduces a settling phase between the self-zeroing and amplification phases of the ping-pong module, significantly reducing output glitches caused by amplifier settling time. This invention operates stably without an external output capacitor, supports a wide input and output voltage range, and possesses excellent characteristics such as low noise, high power supply rejection, and fast response, making it suitable for various demanding high-voltage power supply applications.

This utility model belongs to the field of marine technology, specifically relating to a multi-level equalization management system for marine lithium battery packs. It includes a main control chip, a voltage detection circuit, a current detection circuit, a temperature sensor, and an equalization switch array. By employing a voltage detection circuit composed of operational amplifiers and voltage divider resistors, a current detection circuit composed of Hall effect sensors and low-noise amplifiers, temperature sensors arranged at multiple locations within the battery pack, and an equalization switch array composed of transistors, it achieves high-precision acquisition and rapid response control of battery parameters. This solution improves the system's stability and equalization efficiency in complex environments, effectively solving the problems of untimely and inaccurate equalization control caused by insufficient monitoring accuracy and response lag in existing technologies, thereby significantly improving the safety and service life of marine lithium battery packs.

The utility model provides a high-power LED light source driving circuit, which comprises a direct-current power supply, an LED driver, a charging control circuit, a current sampling resistor, a capacitor bank and a discharging control circuit, a direct-current power supply is input to the LED driver, and the LED driver is connected with the current sampling resistor and the capacitor bank in series. The capacitor bank is connected with the anode of the LED light source; the charging control circuit comprises a voltage division circuit I and a voltage comparator I, and the voltage division circuit I samples the voltage output by the LED driver; the voltage comparator I is connected with the LED driver; the LED driver judges whether the capacitor bank is charged or not; the discharge control circuit comprises a controller and a switching device, the switching device is connected to the controller, and the controller controls on and off of the switching device; when the switching device is switched on, the capacitor bank releases electricity to the light source, and the light source is turned on; large current is provided for the light source through energy storage of the capacitor bank, smooth starting of the large-power light source is guaranteed, and the problems of power consumption increase and transmission cable heating are avoided.

The utility model relates to the technical field of battery testing, in particular to a novel voltage sampling circuit of a battery assembly testing system. The system comprises a sampling unit; the circuit is characterized in that the circuit further comprises a voltage dividing unit, the input end of the voltage dividing unit is used for being connected with the detected high voltage, the output end of the voltage dividing unit is connected with the sampling unit through a low-voltage cable, the voltage dividing unit is used for converting the detected high voltage into a low-voltage signal and transmitting the low-voltage signal to the sampling unit through the low-voltage cable, and the cost of the circuit is low.

This disclosure provides a low-dropout linear regulator (LDO), comprising: an error amplifier, a buffer, a power transistor, a voltage divider negative feedback unit, and a temperature detection unit. The error amplifier includes at least a first output load and a second output load, wherein the equivalent output impedance of the second output load is greater than the equivalent output impedance of the first output load. The temperature detection unit is used to detect the current operating ambient temperature. When the current operating ambient temperature is greater than or equal to a first temperature threshold, the temperature detection unit drives the error amplifier to use the second output load as the current output load. This disclosure performs real-time detection of the operating ambient temperature through the temperature detection unit. When the detected ambient temperature exceeds the temperature threshold, an enable signal is generated to drive the error amplifier to switch its output load, changing its current output load to an output load with a higher equivalent impedance. This improves the gain of the error amplifier, thereby increasing the loop gain and ultimately improving the accuracy of the LDO output voltage.

This invention discloses a high-precision adjustable voltage divider, belonging to the field of high-voltage electrical measurement technology. It includes a high-voltage arm body, a low-voltage precision resistor module, an adjustable potentiometer, and a housing. The high-voltage arm body is a series of high-resistance, medium-precision resistors, undertaking the main high-voltage voltage division. The low-voltage precision resistor module is connected in series at the end of the high-voltage arm for coarse adjustment to correct resistance deviations and improve basic accuracy. The adjustable potentiometer is connected in series or parallel to the low-voltage precision resistor module circuit, with its adjustment terminal exposed in the housing, for final precise calibration of the voltage division ratio. The high-voltage arm body and the low-voltage precision resistor module are integrally insulated and sealed, with only the adjustable potentiometer's adjustment terminal exposed, thus not affecting high-voltage insulation performance. This invention solves the problems of difficult accuracy control, lack of on-site fine-tuning, low production yield, and high calibration costs of traditional high-voltage dividers by using a three-stage resistance adjustment architecture of main body voltage division + precision module coarse adjustment + potentiometer fine adjustment, combined with flexible series and parallel adjustment methods. It can quickly calibrate the voltage division ratio to metrological-grade accuracy, is structurally safe, easy to debug, and highly versatile, suitable for DC, AC, and RC high-voltage dividers.

This utility model discloses a nickel-metal hydride battery management system and its voltage sampling circuit. The voltage sampling circuit includes N batteries connected in series, N pairs of signal coupling devices, and a control device. Each pair of signal coupling devices corresponds to one battery. Each pair of signal coupling devices includes a first signal coupling device and a second signal coupling device. The output terminal of the first signal coupling device is connected to the positive terminal of the corresponding battery and a voltage divider resistor, respectively. The output terminal of the second signal coupling device is connected to the negative terminal of the corresponding battery and a voltage divider resistor, respectively. The control device is configured to output control signals to the signal coupling devices and receive the voltage divider signals from the voltage divider resistors. Through the arrangement of the signal coupling devices, batteries, and voltage divider circuit, voltage sampling of a single battery can be achieved, thereby realizing voltage sampling of the nickel-metal hydride battery.

The utility model relates to the field of switching circuits, in particular to a PMOS (P-channel Metal Oxide Semiconductor) switching circuit, which is characterized in that a source electrode of a PMOS tube Q1 is connected with an input voltage end Vi n, and a drain electrode is connected with a load output end Vout; a base electrode of the triode Q2 receives the switching signal through a control signal end PWR, and an emitting electrode of the triode Q2 is grounded; the first divider resistor R1 is connected between the grid electrode of the PMOS tube Q1 and an input voltage end Vi n; the second divider resistor R2 is connected between the grid electrode of the PMOS tube Q1 and the collector electrode of the triode Q2; the first capacitor C1 is connected between the grid electrode and the source electrode of the PMOS tube Q1; the resistance value ratio of the first divider resistor R1 to the second divider resistor R2 is 1: 3 to 1: 5, the capacitance value of the first capacitor C1 is 10 nF to 100 nF, and the load capacitance C2 does not exceed 470 [mu] F. The voltage division ratio of R1 / R2 is matched with the capacitor C1, so that the conduction time of the PMOS is prolonged, the instantaneous charging current peak value of the load capacitor C2 is remarkably reduced, voltage drop is avoided, and the stability of the system is guaranteed.

This invention provides a three-phase AC input phase loss isolation detection circuit and its detection method based on optocouplers, belonging to the field of detection circuit technology. The invention includes: a half-wave rectifier circuit, a voltage divider circuit, a logic circuit, and an isolated output circuit. The A-phase sinusoidal AC input voltage and the B-phase sinusoidal AC input voltage are connected to the first and second input terminals of the voltage divider circuit respectively through the half-wave rectifier circuit. The C-phase sinusoidal AC input voltage is connected to the third input terminal of the voltage divider circuit. The first and second output terminals of the voltage divider circuit are both connected to the isolated output circuit through the logic circuit. This invention uses a fully analog circuit and employs a wired-AND structure instead of AND gates, resulting in lower cost and lower power consumption compared to digital detection circuits. Furthermore, the output level of the detection circuit conforms to TTL levels and can be directly used in control chips for digital control. The output of the detection circuit is isolated through optocouplers, making the output safer.

The utility model discloses a kind of multistage drive circuit of power switch module, motor controller and vehicle, it includes drive isolation module, power module, 3n pull-up resistors, 3n current-limiting resistors, 12m voltage divider and the number of gate of power switch module equal pull-down resistor, power module is connected with the 3n output end of MCU by 3n pull-up resistors, the 3n input end of drive isolation module is connected with the 3n output end of MCU by 3n current-limiting resistors, the 12m output end of drive isolation module is connected with the gate of power switch module and pull-down resistor by 12m voltage divider. Using the utility model can realize multistage drive current regulation, it is favorable to reduce switching loss, improve the working efficiency of motor controller.

This utility model relates to the field of high-voltage electrical equipment technology, specifically disclosing a voltage divider tube with a high-insulation semi-conductive inner shield. The voltage divider tube body comprises, from the inside out, an insulating core layer, a semi-conductive shield layer, and a high-insulation outer sheath. The resistivity of the semi-conductive shield layer exhibits a gradient distribution, and the dielectric strength of the high-insulation outer sheath is ≥30kV / mm. This utility model, through its three-layer composite structure of the insulating core layer, gradient semi-conductive layer, and high-insulation outer sheath, solves the problem of partial discharge caused by electric field concentration in traditional voltage dividers, achieving a uniform axial electric field gradient distribution and reducing the maximum field strength by more than 40%.

A failure detection circuit (103) for detecting an abnormality in an inrush current prevention circuit (102) which includes an inrush resistor (200) and an inrush relay (201) that are arranged in parallel comprises: a resistive voltage divider circuit (301) that divides a voltage across both ends of an inrush current prevention circuit (102); an amplification circuit (302) that amplifies the difference between the voltages obtained by dividing the voltage by the resistive voltage divider circuit (301); a peak hold circuit (303) that performs temporary peak hold of the voltage divided by the resistive voltage divider circuit (301); and a control unit (304) that, on the basis of respective signals output from the amplification circuit (302) and the peak hold circuit (303), detects a disconnection failure of the inrush resistor (200), a short-circuit failure of the inrush relay (201), and an open failure of the inrush relay (201), wherein the amplification circuit (302) and the peak hold circuit (303) are connected in parallel between the resistive voltage divider circuit (301) and the control unit (304).