摘要:
A coil load driving circuit in which generation of radiation noise when a motor is stationary is minimized, includes output buffers that output a PWM pulse to both terminals of a motor; a transfer voltage generating circuit that outputs transfer voltages VTR1, VTR2 proportional to the difference between an input control voltage VIN and input reference voltage VREF; PWM comparators that output PWM signals PW1, PW2 corresponding to the transfer voltages VTR1, VTR2; and an output PWM pulse synthesis circuit that controls the output buffer in accordance with an AND signal of the PWM signal PW1 and an exclusive OR signal EX of the PWM signals PW1 and PW2, and controls the output buffer in accordance with an AND signal of the PWM signal PW2 and the exclusive OR signal EX.
摘要:
A method and apparatus for driving a capacitive element are provided wherein: (i) when charging the capacitive element by driving and controlling both electrodes of the capacitive element, the capacitive element is charged by setting one of the driving circuits for varying one of the electrode potentials first at a high impedance and then at a low impedance; and (ii) when discharging the capacitive element by driving and controlling both electrodes of the capacitive element, the capacitive element is discharged by setting one of the driving circuits for varying one of the electrode potentials first at a high impedance and then at a low impedance.
摘要:
A current detecting resistor is inserted in an H-bridge circuit constructed to cause the flow of a current to an inductive load in both forward and reverse directions by four semiconductor switching elements and flywheel diodes respectively connected in reverse parallel to the semiconductor switching elements. An inductive load driving method and an H-bridge circuit control device prevent an erroneous operation caused by noise generated at the current detecting resistor. When a current flowing through the inductive load is controlled by a detection voltage generated by the current detecting resistor, the value of the detection voltage is ignored immediately after the connection of the inductive load to a power source. There is no risk that an erroneous operation is caused by a rush current and/or a through current. When a power source regeneration is made to decrease a switching current, the inductive load is connected to the power source at a predetermined period and a current flowing at that time is detected as the detection voltage. There is no risk that the current becomes too small or the transfer to a steady is made while the current is large.
摘要:
An H-bridge circuit which includes four power transistors (an npn pull-down and a pnp pull-up for each of the output terminals). Two control circuits are connected to drive these transistors in a complementary crossover configuration, so that each control circuit can turn on the pull-up transistor on one side of the load and the pull-down transistor on the opposite side of the load. Each of the power transistors is paralleled (base-to-base) by a smaller transistor which provides a scaled current output (proportional to that of the corresponding power transistor) to the opposite control circuit. The control circuit includes static current-thresholding disable logic, which prevents turn-on until the currents through the opposite power devices have declined to threshold levels. Thus, as long as either control circuit is driving one of the pull-up transistors into in the on-state, the other control circuit will not be able to turn on the pull-down transistor which is in series with the active pull-up transistor. This efficiently prevents any condition of unlimited crowbar current, without adding any excess delay or causing any high-impedance condition at the output.
摘要:
The invention is directed to a current regulator for an electromagnetic load used in conjunction with an internal combustion engine. The regulator produces positive and/or negative currents flowing through an electromagnetic load. In this arrangement, the two potentials present at a precision resistor that is connected in series with the load are adjusted to freely selectable values. To obtain both positive and negative currents, the current defined by the voltage drop occurring along the precision resistor is provided by a bridge circuit made up of four current-controlling arrangements. Allowance can be made for particular operating conditions of the current regulator simply by presetting desired values.
摘要:
This invention relates to a control circuit for a motor for use in driving an electrically controlled door such as an air mixing door, inner and outer surrounding air ventilation door, and mode change-over door etc. or an electro-magnetic solenoid for operating an injection pump applied in a Diesel engine or another motor for use in opening or closing a window pane etc. and protects the transistors forming the control circuit.