JPS62143264U - - Google Patents

Description

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the motor rotation speed detection circuit of the present invention, and Fig. 2 is a waveform diagram output by the circuit of Fig. 1. Output points A, B, C, D, E in Figure 1
3 is a circuit diagram of a specific example of the circuit according to the present invention, and FIG. 4 is a relationship between the motor rotation speed actually measured by the circuit of FIG. 3 and the output control signal. FIG. 5 is a block diagram of an example of a conventional motor rotation speed detection circuit, and FIG.
The figure is a waveform diagram output by the circuit in Figure 5.
, b, c, d, e, f, g, and h are waveform diagrams corresponding to input/output points A, B, C, D, E, F, G, and H in FIG. Note that 1: waveform shaping circuit, 2: differentiation circuit, 4:
Input terminal, 5: Output terminal, 6: Amplification circuit, 7: Schmitt circuit, 8: Timing circuit, 9: Sample and hold circuit, 10: Comparison circuit, 11: DC amplifier circuit.

Claims (1)

[Scope of utility model registration request] In a rotational speed detection circuit for a brushless motor that controls the selection of a plurality of drive coils disposed around a rotor made of multi-pole magnetized magnets and the direction of flowing current to rotate the brushless motor in a fixed direction, the drive A motor that obtains DC voltage by shaping and smoothing either the positive or negative output obtained by shaping and differentiating the pulse signal related to the frequency that changes in response to the change in rotational speed detected by one of the coils. rotation speed detection circuit.