摘要:
A current regulator includes a first current source to provide a reference current varying with a dimming step, and a second current source to generate a drive current for a white LED according to the reference current. The reference current and the dimming step have a relationship identical to or approximating a relationship between luminance and lightness perceived by human eyes. Thus, the white LED is controlled to have a linear variation of the luminance perceived by human eyes when the dimming step is changed.
摘要:
A single-ended operational amplifier includes an output stage, a first transconductance amplifier and a second transconductance amplifier. In an offset cancellation mode, two inputs of the first transconductance amplifier are supplied with a reference voltage to sink two currents from two inputs of the output stage respectively, the output stage generates a third current according to the difference between the two currents to charge a capacitor, and the second transconductance amplifier generates two currents according to the voltage in the capacitor to make currents in the two inputs of the output stage equal to each other, thereby canceling the offset of the single-ended operational amplifier.
摘要:
A dimming method for LED driving circuit is proposed. By temporary switching a pin that is originally used for the input/output of other electric signals to a high impedance node, the dimming control signal may be inputted to dim LEDs. The dimming method comprises the steps of: floating the pin every a period of time to pull the pin's voltage being equal to the dimming control signal; detecting the pin's voltage; and retrieving the dimming control signal in accordance with the detected pin's voltage and thereafter dimming the LEDs.
摘要:
A fluid jet head with driving circuit of a heater set. A first and a second primary transistor are coupled to a first and a second heater. When the first primary transistor is turned on under control of a first control voltage and a first current is generated flowing through the first heater, the first primary transistor, and the first current path, then the first primary transistor has a first primary equivalent resistance corresponding to the first control voltage. When the second primary transistor is turned on under control of a second control voltage, and a second current is generated flowing through the second heater, the second primary transistor, and a second current path, then the second primary transistor has a second primary equivalent resistance corresponding to the second control voltage. Therefore, the thermal energy generated by the first heater is substantially equal to that generated by the second heater.
摘要:
The present invention provides a fluid injection head structure and a method of fabricating the same. The fluid injection head structure is disposed on a substrate and has a bubble generator, a functional device for control the bubble generator, a first conductive trace composed of poly-silicon, a chamber, a manifold in flow communication with the chamber, and a second conductive trace. The second conductive trace electrically couples the functional device with the bubble generator and the first conductive trace. Moreover, the chamber further has at least one orifice through the substrate and a gate and the first conductive trace are formed in the same photo-etching process (PEP).
摘要:
A piezo-resistive thermal detection apparatus for detecting the temperature of fluid inside a cavity device, such as the temperature of ink inside an inkjet print head. The apparatus includes a detection region and a plurality of piezo-resistive devices. The detection region is disposed on the inkjet print head in the form of a rectangle and made of a semiconductor material. The piezo-resistive devices are disposed on centers of each side of the detection region, wherein stresses produced by deformation of the piezo-resistive devices are exerted on the piezo-resistive devices. When the temperature of the ink rises, the surface of the inkjet print head is heated and expands, resulting in the deformation of the thermal detection apparatus. The piezo-resistive devices experience large amounts of stress due to the deformation of the thermal detection apparatus and thus the resistances of the piezo-resistive devices change. The piezo-resistive devices are connected together in the form of a circuit bridge so that a voltage signal indicative of the changes in their resistances can be outputted. According to the voltage signal outputted, the temperature of the ink is obtained.
摘要:
The present invention discloses an adaptive two-stage voltage regulator and a method for controlling the same. The adaptive two-stage voltage regulator includes: a voltage regulator for converting an input voltage (Vin) to a middle voltage (Vm), wherein Vin≦Vin_max; a linear regulator for converting the middle voltage to an output voltage (Vout); and a middle voltage controller for adjusting the middle voltage according to (1) an input voltage indicator and one of (2a) an output voltage indicator and (2b) a predetermined reference signal, such that when Vin≦Vout, Vm=Vout+ΔV and (Vout+ΔV)
摘要:
A non-synchronous boost converter includes a low-voltage device connected between the input voltage terminal and the output voltage terminal of the converter. When the converter is shutdown, the low-voltage device disconnects the output voltage terminal and the input voltage terminal. Since it is a low-voltage device used in the converter for load disconnection, the efficiency of the converter is improved with lower cost.
摘要:
For efficiency improvement of a LED display system including a charge pump and a LED connected to either the voltage input terminal or the voltage output terminal of the charge pump, either one or both of two current regulators are enabled according to a voltage detected from the LED, for establishing a driving current for the LED. When the detected voltage is higher than a threshold, the first one of the current sources is enabled sole. When the detected voltage is lower than the threshold, the second one of the current sources is enabled sole, or both the current sources are enabled, or the current sources are alternatively enabled.
摘要:
The present invention discloses a single-wire transmission interface, and a method of transmission through single-wire. The method comprises: providing a single-wire signal through a single-wire; and transmitting information only in a transmission period defined by a fixed first time period starting from one of a rising or a falling edge of the single-wire signal.