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Peak current buzzer driving circuit

A technology of peak current and driving circuit, applied in the direction of instruments, sounding equipment, etc., can solve the problems of high power consumption, poor sound pressure consistency, high cost, and achieve the effect of reducing power consumption, good sound pressure consistency, and low power consumption

Active Publication Date: 2019-11-19
SHENZHEN NANYUN MICROELECTRONICS CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is to provide a peak current type buzzer drive circuit to solve the problems caused by the high cost, high power consumption and poor sound pressure consistency of the existing buzzer drive circuit under high input voltage. The problem of narrow applicable input voltage range

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0086] like Figure 3 to Figure 8 As shown, the present invention discloses a peak current type buzzer driving circuit, which includes a switch tube 106 and a control unit 300. When the switch tube 106 is turned on, it connects the electromagnetic buzzer 109 and the system input voltage VIN , disconnect the electromagnetic buzzer 109 from the system input voltage VIN when it is turned off, and the control unit 300 is used to output a PWM signal, so that: the switching tube 106 is turned on when the PWM signal is at a high level , turn off when the PWM signal is at low level;

[0087] The control unit 300 is provided with a sampling circuit 107, the sampling circuit 107 includes a sampling resistor connected in series with the switching tube 106, and the control unit 300 is based on the system input voltage VIN and the electrical signal on the sampling resistor, Dynamically output PWM signals that meet the following conditions:

[0088] Condition 1. The period T of the PWM si...

Embodiment approach

[0098] like image 3 As shown, the control unit 300 is also provided with a feedforward voltage generation module 200, a comparator module 102, a logic drive module 103, an oscillator 104, a power supply module 105 and a freewheeling module 108;

[0099] The positive pole of the electromagnetic buzzer 109 is connected to the system input voltage VIN, the negative pole is connected to the drain of the switching tube 106, and the source of the switching tube 106 is connected to the reference ground terminal GND through the sampling resistor;

[0100] The power module 105 converts the system input voltage VIN into a bias voltage VDD for powering the control unit 300; the power module 105 is preferably an LDO module.

[0101] The feedforward voltage generating module 200 outputs a real-time feedforward voltage V satisfying the following formula 2 ref (t):

[0102]

[0103] The sampling circuit 107 outputs the real-time voltage V of the sampling resistor CS (t), namely: V CS...

Embodiment 3

[0114] On the basis of the above-mentioned embodiment two, the present embodiment three also adopts the following preferred implementation modes:

[0115] The second formula is linearized so that: the real-time feedforward voltage V output by the feedforward voltage generation module 200 ref (t) satisfy the following formula four:

[0116]

[0117] V ref (t)=K C V in (t)+V ref min [formula four];

[0118] In the formula, V in max is the maximum value of the system input voltage VIN;

[0119] Make: the real-time duty ratio D (t) of described PWM signal changes according to following formula three:

[0120]

[0121] Therefore, the present embodiment three aims at the existence of the above-mentioned formula one and formula two As a result, when the control unit 300 is implemented by an integrated circuit, it is difficult to debug the circuit parameters of the integrated circuit to fully satisfy the formulas 1 and 2. By setting the real-time feed-forward voltage V...

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Abstract

The invention discloses a peak current buzzer driving circuit. The peak current buzzer driving circuit is characterized in that a period T of a PWM signal is set as a fixed value through a condition I, and the real-time duty ratio D(t) of the PWM signal changes reversely along with the real-time voltage value V<in>(t) of a system input voltage. Moreover, the real-time duty ratio D(t) of the PWM signal is controlled through a formula I set according to a condition II. Under a high system input voltage, the real-time duty ratio D(t) can be decreased in order to guarantee the normal work of an electromagnetic buzzer; the problem that the sound pressure of the electromagnetic buzzer under the high system input voltage is over low since the decreasing amplitude of the real-time duty ratio D(t)is over large can be solved; and the change of the sound voltage of the electromagnetic buzzer is relatively small within a wide system input voltage range. As proved by verification, the sound voltage deviation of the electromagnetic buzzer can be controlled within + / -3db in a wide input range of 3 to 24VDC. Thus, the peak current buzzer driving circuit can be compatible with a relatively wide system input voltage range, and can ensure low power consumption and high sound pressure consistence within a wide system input voltage range.

Description

technical field [0001] The invention relates to a peak current type buzzer driving circuit. Background technique [0002] The traditional electromagnetic buzzer driving circuit generally uses a triode and a transformer to form a self-excited oscillation circuit, such as figure 1 shown. First, when the circuit is powered on, the base junction capacitance of Q1 is charged through R1. When the voltage of the base junction capacitance reaches the transistor opening threshold, the transistor Q1 is turned on, and the VCC terminal voltage source passes through the transistor Q1 to the excitation inductance of the buzzer. L1 charges. In addition, an upper positive and lower negative induced electromotive force is generated at the same-named end of the inductor L1 / L2, and the current direction in the form of the electromotive force generated at both ends of L2 flows out from the same-named end, prompting the switch tube Q1 to be in a saturated conduction state. When the current of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G10K9/13
CPCG10K9/13
Inventor 尹向阳黄天华赵永宁
Owner SHENZHEN NANYUN MICROELECTRONICS CO LTD