PCA2000U中文资料32 kHz watch circuit with programmable adaptive motor pulse数据手册恩XP规格书

描述 Description

The PCA2000 and PCA2001 are CMOS integrated circuits for battery operated wristwatches with a 32 kHz quartz crystal as timing element and a bipolar 1 Hz stepping motor.The quartz crystal oscillator and the frequency divider are optimized for minimum powerconsumption. A timing accuracy of 1 ppm is achieved with a programmable, digitalfrequency adjustment.
To obtain the minimum overall power consumption for the watch, an automatic motorpulse adaptation function is provided. The circuit supplies only the minimum drive current,which is necessary to ensure a correct motor step. Changing the drive current of themotor is achieved by chopping the motor pulse with a variable duty cycle. The pulse widthand the range of the variable duty cycle can be programmed to suit different types ofmotors. The automatic pulse adaptation scheme is based on a safe dynamic detection ofsuccessful motor steps.
A pad RESET is provided (used for stopping the motor) for accurate time setting and foraccelerated testing of the watch.
The PCA2000 has a battery End Of Life (EOL) warning function. If the battery voltagedrops below the EOL threshold voltage (which can be programmed for silver oxide orlithium batteries), the motor steps change from one pulse per second to a burst of fourpulses every 4 seconds.
The PCA2001 uses the same circuit as the PCA2000, but without the EOL function.

特性 Features

Amplitude-regulated 32 kHz quartz crystal oscillator, with excellent frequency stabilityand high immunity to leakage currents
Electrically programmable time calibration with 1 ppm resolution stored in One TimeProgrammable (OTP) memory
The quartz crystal is the only external component connected
Very low power consumption, typical 90 nA
One second output pulses for bipolar stepping motor
Minimum power consumption for the entire watch, due to self adaptation of the motordrive according to the required torque
Reliable step detection circuit
Motor pulse width, pulse modulation, and pulse adaptation range programmable in awide range, stored in OTP memory
Stop function for accurate time setting and power saving during shelf life
End Of Life (EOL) indication for silver oxide or lithium battery (only the PCA2000 hasthe EOL feature)
Test mode for accelerated testing of the mechanical parts of the watch and the IC
Test bits for type recognition
Target ApplicationsDriver circuits for bipolar stepping motors
High immunity motor drive circuits

应用 Application

Driver circuits for bipolar stepping motors
High immunity motor drive circuits