Inductive load voltage pulse width modulation magnetism releasing circuit

Abstract

The invention discloses an inductive load voltage pulse width modulation magnetism releasing circuit. The inductive load voltage pulse width modulation magnetism releasing circuit comprises an input protection rectifying circuit and a main demagnetizing circuit. The main demagnetizing circuit is composed of a pulse width modulation control NMOS tube M1, a load L1, a fly-wheel diode D6, a demagnetization voltage-stabilizing diode D8 or a resistor R3, a bootstrap boost capacitor C1, a bootstrap boost auxiliary diode D7, a bootstrap boost capacitor charging and discharging loop control diode D10 (removable), a voltage-dividing resistor R1, a voltage-dividing resistor R2, a pulse width modulation stage conducting NMOS tube M2 (or a triode) and an anti-NMOS tube breakdown voltage-stabilizing diode D9 (removable). The inductive load voltage pulse width modulation magnetism releasing circuit is fast in response speed, can meet the current condition that the response speed of the inductive load is controlled by voltage pulse width modulation, is simple in circuit, low in circuit cost and wide in application range, and can be suitable for various of circuits with the inductive load controlled by the voltage pulse width modulation.

Description

technical field [0001] The invention relates to a voltage pulse width modulation magnetic release circuit, in particular to an inductive load voltage pulse width modulation magnetic release circuit. Background technique [0002] With the rapid development of electronic technology, voltage pulse width modulation technology is more and more applied to various fields because it only needs to change the duty cycle to complete the linear control of the controlled object. Among them, the most widely used one is to control the MOS tube switch through the voltage pulse width modulation technology, and at the same time use the freewheeling diode to control the constant current of the inductive load, but every time the inductive load is cut off, due to the existence of the freewheeling diode and the current on the inductive load The reason for the inability to change abruptly is that the energy accumulated on the inductive load cannot be quickly released, resulting in a slow cut-off. ...

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Problems solved by technology

Among them, the most widely used one is to control the MOS tube switch through the voltage pulse width modulation technology, and at the same time use the freewheeling diode to control the constant current of the inductive load, but every time the inductive load is cut off, due to the existence of the freewheeling diode and the current on the inductive load The reason for the inability to change abruptly is that the energy accumulated on the inductive load cannot be quickly released, resulting in a slow cut-off. The traditional solution is to connect a Zener diode and a freewheeling diode in series to realize freewheeling as a whole, or to A resistor and a freewheeling diode are connected in series to realize freewheeling as a whole. However, since the voltage pulse width modulation requires a high-speed switching MOS tube to control the current, it will cause the above-mentioned freewheeling to be frequently switched on and off, resulting in frequent switching of the Zener diode. The breakdown and the current flowing through the resistor are relatively large, which eventually leads to a large power consumption on the Zener diode or the resistor, so the traditional method cannot solve the above problems well, which requires a circuit to control the high-speed switching MOS tube in the voltage pulse width modulation When the inductive load is inductive, the Zener diode (or resistor) does not work, and when the inductive load is cut off, the Zener diode (or resistor) works, which can reduce the power consumption of the diode (or resistor)

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