Electronic circuits provide an error signal to control a regulated output voltage signal generated by a controllable DC-DC converter for driving one or more series connected strings of light emitting diodes.

Electronic circuits for driving series connected light emitting diode strings

An electronic circuit includes circuit portions for identifying a largest voltage drop through one of a plurality of series connected diode strings and for controlling a boost switching regulator according to the largest voltage drop. The electronic circuit can sense an open circuit series connected diode string, which would otherwise have the largest voltage drop, and can disconnect that open circuit series connected diode string from control of the boost switching regulator. Another electronic circuit includes a current limiting circuit coupled to or within a boost switching regulator and configured to operate with a diode load. Another electronic circuit includes a pulse width modulation circuit configured to dim a series connected string of light emitting diodes.

Electronic circuit for driving a diode load

Electronic circuits and methods include provisions for passing a first current through a diode during a first time interval and for passing a second different current through the diode during a second different time interval. The first current is selected to achieve a predetermined voltage at a node of the diode. A duty cycle of the first current relative to the second current is selected to achieve a predetermined average current passing through the diode. In some arrangements, the diode is a light emitting diode.

Electronic circuit for driving a diode load with a predetermined average current

Audio communication apparatus which facilitates reduction of data network traffic The communication apparatus distinguishes between voice activity and silence or background noise Upon termination of voice activity the apparatus output the contents of it memory thus far for transmission over the data network When voice activity is resumed after a period of inactivity, the transmission of voice data is resumed and an indication of the elapsed time between the previous voice samples and the current samples is also transmitted to a receiving terminal to allow correct timing of the output of the resumed transmission of the voice samples

Method and apparatus for audio communication

An electronic circuit, referred to as an on-time extension circuit herein, provides an ability to adjust a power delivered to a load by pulsing a predetermined current to the load. The on time of the a DC-DC converter used to provide the power is extended to be longer than the on time of the current pulse when the on time of the current pulses becomes very short.

Electronic circuits and techniques for improving a short duty cycle behavior of a DC-DC converter driving a load

PURPOSE:To process the addition and the subtraction at one time by using a voltage/current converter containing an emitter negative feedback resistance and a differential amplifier set at the output stage of the voltage/current converter. CONSTITUTION:A voltage/current converter A which converts the input signal voltage into a logarithmic function is provided together with a differential amplifier B having high gains which secures the single output from the output of the converter A. Thus an operational amplifier circuit is obtained. A signal input stage converts the input signal voltage into a differential current via the emitter negative feedback resistances R1 and R2 and supplies the differential current to a diode D2. Then a transistor differential pair is biased with the forward voltage of the diode D2. Thus the single output is obtained. Thus an accurate operation is secured despite a high impedance of a signal source.

Multi-input operational amplifier circuit and integrating circuit using the amplifier circuit

PURPOSE:To improve adhesion properties of an electrode and prevent parasitic capacity from being generated by forming one electrode of the capacitor in doped polysilicon layer. CONSTITUTION:An island region 2a is formed at a semiconductor substrate where an N type epitaxial layer 2 is subjected to vapor growth on a P-type semiconductor substrate 1. A doped polysilicon layer 5 with conductivity is clad on the main surface of a thermal oxide film 4 at the upper part of the island-shaped region 2a, thus forming one electrode of a capacitor. A capacitor dielectric layer is formed on the main surface of the doped polysilicon layer 5 by thermal oxidation treatment. A metal foil film layer 7 such as aluminum is clad on the main surface of the oxide film 6, thus forming the other electrode of capacitor. Since this capacitor has extremely small combined parasitic capacity generated in series, it can be used for a high-frequency capacitor, etc.

Toyama Tsuneo

Papers

Multi-input operational amplifier circuit and integrating circuit using the amplifier circuit

Capacitor formed in semiconductor device and manufacture thereof