Showing papers on "H bridge published in 1995"

Electric drives for pump, fan, and compressor loads in automotive applications

Abstract: Optimization of automotive power plants is moving in the direction of increased utilization of electrically driven auxiliary loads. Such subsystems include cooling and power assist functions. The power levels required by these loads range from hundreds to tens of hundreds of watts. At these power levels, the current ratings of switching devices and motor phase leads, assuming tradition drive and motor designs, can exceed 100 amps at the standard 13.5 VDC bus level. This paper discusses alternative drive and motor configurations which will mitigate the current rating requirements of the drive and motor components. The authors present the case for usage of H-bridge and bipolar bus drives and usage of five-phase machines.

Circuit and method for measuring current in an H-bridge drive network

Abstract: A circuit measures the driving and circulating current in an H-bridge drive network directly and linearly. Voltage across two current sensing resistors are input to two precision half-wave rectifiers. The output of the rectifiers are input to a differential amplifier via a circuit of resistors. The output of the differential amplifier is a signal representative of the current in the H-bridge for both the driven periods and non-driven or freewheeling periods.

Push-and-pull driver circuit for driving an H-bridge coupled to a two-terminal inductive load

Abstract: A write driver for a two-terminal inductive load comprises an H-bridge switching circuit and a push-pull driver circuit. The H-bridge switching circuit responds to a first mode to conduct a current in a first direction through the inductive load and responds to a second mode to conduct the current in a second direction through the inductive load. The push-pull driver circuit responds to the first mode to push a charge current into a first control node of the H-bridge and responds to the second mode to pull a discharge current from the first control node. In one form, the write driver includes a second push-pull driver circuit responsive to the first mode to pull a discharge current from a second control node and to the second mode to push a charge current into the second control node.

Motor drive circuit

Abstract: PURPOSE:To obtain a power system circuit having simple circuitry by constituting an H bridge such that a current is fed through a single phase induction motor in one direction by transistors applied, respectively, with a pulse signal and a PWM signal and a current is fed in reverse direction for next different active state. CONSTITUTION:A comparator 9 is provided with an inversion unit 71 on the input side thereof and produces a pulse waveform having an active state generating time shifted by a half period of the sine wave from that of a comparator 10. Since a PWM signal is applied to the gate of a Tr5 when the gate of a power MOSFET(Tr)2 is turned ON, current flows through a capacitor motor (CM)6 from the left to the right. When the Tr4 is turned ON, current flows through the motor from the right to the left. Since PWM signals are fed to the gate terminals of the Tr3 and Tr5, sine wave current flows through the CM6 and thereby a smooth motor circuit is obtained.

Driving circuit of dc motor for modifying speed change ratio of variable speed drive

Abstract: PURPOSE:To impart a fail-safe function to an electronic control system for a DC motor generating the operating force for modifying the speed change ratio of a variable speed drive comprising an H bridge circuit of FETs and a microcomputor. CONSTITUTION:A voltage monitoring means 21 monitors the voltages being fed from current supply sections A, B to a DC motor 12 in an H bridge circuit 3 thus detecting the short circuit/open circuit of the circuit 3 and FETs T1, T2, T3, T4 and the open circuit of the DC motor 12. A current monitoring means 24 monitors the current of the H bridge circuit 3 thus detecting short circuit of the DC motor 12. These abnormalities actuate a circuit interrupting means 25 thus stopping the DC motor 12.

Controller of electric motor-driven power steering device

Abstract: PROBLEM TO BE SOLVED: To aim at provision of a calculating means for estimation value of a correct motor angular speed while restricting generation of a vibratory electric current at the time of returning a handle, in the motor control circuit of an electric motor-driven power steering device in which an H bridge circuit is used. SOLUTION: FET1 is driven at a duty ratio D1 and FET3 is driven at a duty ratio D2 longer than FET1 in view of time. D2 is defined by the primary function of D1, namely D2=a.D+b and if a, b are decided by driving condition, a motor electric current I is displayed by such an equation as I=Vb/ R 1-(KTWret/γVb)}.D+KT/R(ωret-ω) so that a vibratory electric current (noise) can be prevented from its generation. Motor angular speed ω can be estimated from a motor inter-terminal voltage VM=(D1+D2-1)Vb obtained from a battery voltage Vb and a duty ratio D1, D2, and a motor electric current value I estimated from a motor electric current detection value and the second duty ratio.

Control circuit for h-type bridge circuit

Abstract: PURPOSE:To provide a control circuit for H bridge circuit which can be miniaturized with high reliability by decreasing the number of externally added elements when it is integrated. CONSTITUTION:The control circuit 7A comprises a capacitor 112, a circuit 110 for charging/discharging the capacitor 112 based on a control signal, circuits 113-116 for detecting the voltage of the capacitor 112, and circuits 83, 87 for holding the control signal based on the detection signal from the voltage detecting circuits 113-116. Charge/discharge of the capacitor 112 is controlled by varying the control signal thus protecting H-type bridge circuits 3a-3d against through current. Upon elapse of charge/discharge interval, the bridge circuit makes a transition to an operating state corresponding to the control signal.

Stepping motor driver

Abstract: PURPOSE:To drive with a constant current without always feeding back a current by so deciding a correction amount of pulse generating means that a real current flowing to an H bridge becomes equal to a specific target current. CONSTITUTION:A stepping motor 10 has two coils of an A-phase coil 12 and a B-phase coil 13 for driving a rotor 1, and currents flowing to the coils are controlled by first and second H bridges 21, 22. Power is supplied from a power source bus 60 to the bridges 21 and 22 through a current detecting resistor 50. Specific target currents flows to phases of the motor 10 in a specific operating state immediately after the power source is turned ON, a correction coefficient is calculated based on a deviation from a real current to be detected by the resistor 50, and the bridge is driven by an open loop control using the coefficient in a normal operating state. As a result, a constant current drive can be always performed without feeding back.

Signal output circuit

Abstract: PURPOSE:To prevent transmission delay time, that is, dead time from being remarkably increased in high temperature without increasing a chip area in a signal output circuit including an output H bridge output circuit and a gate delay circuit. CONSTITUTION:P-Channel MOSFET QP1 and n-channel MOSFET QN2 with small V/L in the gate delay circuit 2A are divided into p-channel MOSFETs QP1, QP3, and n-channel MOSFETs QN2, QN3. Fixed transmission time(dead time) can be secured in environment other than the high temperature by allowing the p-channel MOSFET QP3 and the n-channel MOSFET QN3 to perform a switching operation corresponding to a signal from an input terminal 7 only when a level of 'L' is outputted from a heating-up detection circuit 5 in the high temperature, and the dead time can be prevented from being remarkably increased in the high temperature. The p-channel MOSFET QP1 and the n- channel MOSFET QN2 can be divided into the number >= 2.

Dc motor drive circuit and portable acoustic equipment incorporating it

Abstract: PURPOSE:To eliminate the need for a high drive voltage power supply for a transistor for an upstream side and reduce power consumption and at the same time secure the integration area of other circuits by setting the upstream side of an output stage circuit to P-type bipolar transistor and a downstream side to NMOS transistor. CONSTITUTION:With the H bridge of an output circuit 2 of a DC motor drive circuit, an upstream side and a downstream side are constituted as P-type bipolar transistors Q1 and Q2 and NMOS transistors TR3 and T4, respectively. The power to drive circuit 4 and 6 for driving the P-type bipolar transistors Q1 and Q2 is obtained from 2.4 V power supply drive 17 of a battery 16 and the power of drive circuits 3 and 5 of NMOS transistors TR3 and TR4 is obtained from 3.5V power supply line. Therefore, only one DC/DC converter 13 is required as a power supply for driving motor, thus reducing power consumption and integrating various kinds of other function circuits.

Motor driver circuit

Abstract: PURPOSE:To provide a motor driver circuit without generation vibration and noise even if a motor is used at a high rotation region (1 kpps or higher) using the control by regeneration damping. CONSTITUTION:The title circuit controls the drive of a stepping motor for plotter by inputting the pulse width modulation waveform of input sinusoidal wave to an H bridge 12 and then operating the H bridge 12 and performs the feedback control of the input sinusoidal wave by the feedback loop from the H bridge 12 with an integration circuit 18 for controlling the pulse width modulation waveform. Therefore, the H bridge 12 is connected for regenerative damping and at the same time a capacitor 20 is provided at the downstream position from the integration circuit 18 within a feedback loop.

Constant current controller with abnormality diagnostic function

Abstract: PURPOSE:To diagnose a current sensor and an overcurrent sensor by detecting a current flowing upon simultaneous turn ON of two switching elements connected in series before starting the current control using four switching elements forming an H bridge in a constant current controller. CONSTITUTION:The microcomputor 11 in a controller comprises a CPU 11b, a memory 11c, I/O interfaces 11d, 11e, and an A/D converter 11f disposed around a bus 11a. A drive circuit 14a comprises switching elements 14a1-4 connected in bridge and a drive logic 14a5. Phase A drive coil 12a is connected between a pair of joints of the bridge having the other pair of joints connected with a power supply bus 16 and the earth. A shunt resistor 13a1 for current detection and an overcurrent sensor 15 are connected between the bridge and the power supply bus 16. The voltage across the shunt resistor 13a1 is connected through a butter amplifier 13a2 with the A/D converter 11f.

Power supply circuit for an electroluminescent lmp

Abstract: The power supply circuit for the voltage emitting lamp has one transformer with two windings 4, 6. The primary winding 4 of the transformer is periodically energized by the battery via the H bridge. By using the H bridge, the current circulating in the primary winding 4 does not have a direct current component, and thus the transmission ratio of the electrical energy transferred from the primary winding 4 to the secondary winding is optimized.

Power source for an electroluminescent sheet

Abstract: The circuit includes a transformer, with two windings (4,6), one of which (6) is connected to the electrodes of an electroluminescent film (7). A battery (2), connected to the transformer primary winding, supplies the circuit. An H bridge is connected between the battery and the transformer. The bridge is made up of two p type transistors (T1,T2) and two n type transistors (T3,T4). The transistor gates are connected to a common node (10) via an inverter (8). A microcontroller (12), with a time base, generates a control signal for the transistor bridge.