1. Technical Field
The present invention relates to a startup control circuit of a drive circuit which controls driving of a motor at startup.
2. Background Art
Recently, for a vibration function equipped in portable phones or game machines, a position detecting circuit which uses a Hall element is used for detecting a position of a vibration element.
When a magnet is employed as a rotor and a coil is employed as a stator, the Hall element detects a position of the rotor, and a drive circuit supplies a current to the coil based on a detection result of the Hall element.
There exists a demand for minimizing power consumption in an electronic device, and there also is a demand for minimizing sonic noise generated from the device.
In a vibration motor which has the vibration element in the related art, of the currents supplied to two coils, currents around 0° and 180° do not significantly contribute to the driving of the motor. In consideration of this, an electricity application method which cuts the currents around 0° and 180° of the motor drive current has been proposed. For example, an electricity application method which cuts electricity application for 30° around 0° and 180° is known as 150°-electricity application.
The 150°-electricity application does not have sufficient power, and when the device is to be driven based on the rotational state signal, there has been a problem in that the rotation is not started if the start of the drive coincides with the period where the electricity is not applied.