JPH0334696U - - Google Patents

Description

[Brief explanation of drawings]

Fig. 1 is a specific circuit diagram of the embodiment of the present invention, Figs. 2 and 3 are explanatory diagrams of the same operation as above, Fig. 4 is a sectional view of main parts showing the schematic structure of the conventional example, and Fig. 5 is the same as above. The operating waveform diagram and FIG. 6 are specific circuit diagrams of the same as above. 2... Distribution circuit, 3 ₁ to 3 ₃ ... Gate circuit,
4 ₁ ~ 4 ₃ ...Floating power supply, 5 ₁ ~ 5 ₆
...Transistor bridge, Tr ₁₆ to _{Tr 21}
...It is a power MOSFET.

Claims (1)

[Scope of utility model registration request] A distribution circuit that takes as input a 3-phase position signal with an electrical phase of 2π/3 generated from a position detector of a brushless motor and generates a predetermined signal train necessary for a 3-phase bipolar drive circuit, and an output of this distribution circuit. and a gate circuit that synthesizes the PWM signal for current control, and a set of power MOSFEs by the output of this gate circuit.
The first one drives the lower gate of the T-half bridge.
a floating power supply whose ground is separated by a resistor and a capacitor, and a second transistor bridge which uses the floating power supply as a power supply and drives the upper gate of the power MOSFET half bridge with a distribution circuit output. A brushless motor drive circuit for a rechargeable tool includes a detection means for detecting the speed of the brushless motor, and a power MO when the number of rotations of the brushless motor is below a certain level based on a signal from the detection means.
A brushless motor drive circuit for a rechargeable tool, comprising a control means for turning off an SFET and stopping the brushless motor.