Seiko Epson Corporation

Tsukasa Muranaka

Hajime Miyazaki

Masaaki Handa

Taisuke Uehara

Shinichi Kamisuki

Masahisa Ikejiri

Yasuto Nose

Michio Yanagisawa

Kunihiro Inoue

Tajsuke Uehara

Shouichi Uchiyama

A switching regulator soft start circuit and technique which eliminates variations in frequency and is capable of more appropriately preselecting a suitable operating frequency by using a timer which responds to a start signal by generating an initial condition release signal after a predetermined interval, a frequency divider for obtaining a desired oscillation frequency from the output of a switching regulator, and a first gate element connected to receive the output of the frequency divider and the initial condition release signal, and to provide as an output a gate control signal that varies in frequency corresponding to the frequency divider output whenever the initial condition release signal is off but provides a gate control that delivers undivided switching regulator signals when the initial condition release signal is on; and a gate circuit connected to receive oscillation frequency signals and the gate control signal to control the delivery of output signals.

Switching regulator soft start circuit

A micropump supervisory control method and apparatus having various functions, such as annunciation and safety measures. The control method and apparatus accurately control trace discharge rates through adjustment of the number and frequency of driving pulses for a piezoelectric valve element. In addition, the control method provides discharge, life-prediction and life-expiration warning, and operation acknowledge alarms and annunciations while driving the micropump, each having a predetermined sounding pattern. Micropump functions are also inhibited when a power source is reconnected.

Micropump supervisory control

A micropump particularly suited for use in the fields of medicine and analysis includes a thin membrane plate sandwiched between a surface plate and a glass-made substrate. The intermediate membrane has an inlet valve and an outlet valve and the glass substrate has an inlet port and an outlet port, respectively connected to the corresponding valves. Between the valves formed in the thin membrane plate by means of etching, there is a diaphragm on which there is a piezoelectric element for detecting behavior of the diaphragm. Another micropump has an upper thin membrane plate member and a lower member. The upper member has the inlet valve and the lower member has the outlet valve. An intermediate glass substrate is inserted between the upper and the lower thin membrane plate member.

Two-valve thin plate micropump

A watchdog timer capable of detecting clock signals when the opening frequency of a frequency source drifts lower or higher than a normal desired operating range, increasing circuit safety and reliability. The timer uses first and second clock oscillation circuits to generate first and second signals of frequencies f.sub.1 and f.sub.2 which are then divided by 1/N.sub.1 and 1/N.sub.2 in first and second frequency dividers, respectively. Third and fourth frequency dividers are used to divide the second frequency signal f.sub.2 by 1/N.sub.3 and 1/N.sub.4, respectively. A scale of N.sub.5 counter is connected to receive the f.sub.1 /N.sub.1 frequency signal as a clock input and the f.sub.2 /N.sub.3 frequency signal as a reset input, and provides an output signal at a frequency of (f.sub.1 /N.sub.1)/N.sub.5 which is less than f.sub.2 /N.sub.3 when the clock circuits are operating under normal conditions. A scale of N.sub.6 counter is connected to receive the f.sub.2 /N.sub.4 frequency signal as a clock input and the f.sub.1 /N.sub.2 frequency signal as a reset input, and provides an output signal at a frequency of (f.sub.2 /N.sub.4)/N.sub.6 which is less than f.sub.1 /N.sub.2 under normal conditions. A discrimination circuit is connected to monitor the outputs of the scale of N.sub.5 and N.sub.6 counters to determine the presence of a fault by detecting when either output no longer meets the associated relationship.

Watchdog timer employing plural counters and discriminator for

A humidity sensing apparatus which includes a humidity sensor which detects humidity as a function of impedance is provided. A reference resistor has a predetermined resistance value. A charge switching circuit selectively couples one of the reference resistor or the humidity sensor in series with a reference capacitor which has a predetermined capacitance. A voltage judging circuit determines whether the terminal voltage of the reference capacitor is high or low. A charge/discharge switch selectively charges and discharges the reference capacitor in accordance with the output of the voltage judging circuit. A sensor direction switching circuit inverts the direction of current flowing through the humidity sensor during charging of the reference capacitor. An oscillation frequency counter counts the number of charge/discharge cycles which are repeated during a predetermined time period. A humidity sensor resistance value calculating circuit calculates the resistance value of the humidity sensor in accordance with the number of repeated charge/discharge cycles when the reference capacitor is coupled to the reference resistor for charging and the number of repeated charge/discharge cycles when the reference capacitor is coupled to the humidity sensor during charging. A humidity determining circuit determines the humidity from the resistance value of the humidity sensor calculated by the humidity sensor resistance value calculating circuit.

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Suwa, Japan

Tsukasa Muranaka