iWatt Integrated Circuits Technology (Tianjin) Limited Patent applications |
Patent application number | Title | Published |
20140266217 | METHOD AND SYSTEM FOR DETECTING LED SHORT CIRCUIT IN LED STRINGS OR DETECTING MATCHING AMONG LED STRINGS - This specification relates to a method and a system for detecting light emitting diode (LED) short circuit in a plurality of LED strings or detecting matching among the plurality of LED strings, wherein one end of each of the plurality of LED strings is connected to a same output end of a power supply, and the other end is respectively connected to a corresponding switch. According to the present invention, first current of each of LED strings is obtained when the output end of the power supply outputs a first voltage; differences between the minimum of the first currents of LED strings and other first currents are calculated; the differences are compared with a comparing threshold; it is determined that the LED strings corresponding to the other currents for which differences are larger than the comparing threshold include short circuit or mismatch with the LED string corresponding to the minimum current. Accordingly, it is possible to reduce the number of pins and area of a control chip. | 09-18-2014 |
20140161216 | Apparatus and Method for Reducing Jitter in Periodic Signals - The present invention provides an apparatus and method for reducing jitter in a periodic signal. The apparatus comprises: a frequency discriminator configured to receive the periodic signal and feedback of an output signal of the apparatus and calculate an estimate value for a length of a current period of the periodic signal; a phase discriminator configured to receive the periodic signal and determine an adjustment factor for the length of the current period of an input signal according to the input signal in a previous period of the periodic signal and the output signal in the previous period of the apparatus; and an adjustor configured to determine the period length of the output signal in the current period according to the estimate value for the length of the current period and the adjustment factor for the length of the current period. | 06-12-2014 |
20140152369 | Level Translator Circuit, Driving Circuit for Driving High-Voltage Device and Method Thereof - The present invention provides a level translator circuit, a driving circuit for driving a high-voltage device and a corresponding method. The driving circuit for driving a high-voltage device comprises: a zener diode whose cathode is connected to a high-voltage power supply voltage and whose anode is connected to a ground potential of a low-voltage domain through a resistor; a high-voltage PMOS transistor whose gate is connected to an anode of the resistor, whose drain is connected to the ground potential of the low-voltage domain, and whose source is operable to supply a ground potential of a high-voltage domain; a level translator operable to convert a first signal in the low-voltage domain as received to a second signal in the high-voltage domain and output the second signal; and a low-voltage driving circuit operable to receive the second signal and adapt the second signal as a third signal which can drive the high-voltage device. The present invention allows for use of the low-voltage device to drive the high-voltage device to achieve the drive of the high-voltage device in a simple and efficient manner. | 06-05-2014 |
20140152362 | Duty Cycle Adjusting Circuit and Adjusting Method - The present invention relates to a square wave generator circuit, an integrated circuit, a DC/DC converter and an AC/DC converter. The square wave generator circuit comprises a first mirror current branch which is connected with ground via a first switching element and a first capacitor in parallel with the first switching element, wherein the first switching element is operable to be opened or closed periodically under control of a first clock signal so as to generate a first sawtooth wave signal at a non-grounded terminal of the first capacitor; a second mirror current branch which is connected with ground via a second switching element and a second capacitor in parallel with the second switching element, wherein the second switching element is operable to be opened or closed periodically under control of a second clock signal synchronous with the first clock signal so as to generate a second sawtooth wave signal at a non-grounded terminal of the second capacitor; and a comparator, one input terminal of which is connected to the non-grounded terminal of the first capacitor and the other input terminal of which is connected to the non-grounded terminal of the second capacitor, so that a square wave signal can be outputted at an output terminal of the comparator, wherein a duty cycle of the square wave signal depends on a ratio of a capacitance of the second capacitor to a capacitance of the first capacitor. | 06-05-2014 |
20140152289 | Reference Voltage Generator Circuit - Various embodiments of the present invention relate to a reference voltage generator circuit. Specifically, the circuit may for example comprise: a mirror constant current source having a first branch and a second branch, wherein a first current on the first branch is proportional to a second current on the second branch; wherein the first branch has a first resistive element, and the second branch has two second resistive elements connected in series; and a power supply terminal located between said two second resistive elements on the second branch. A high-precision reference voltage relative to the voltage source can be provided at the power supply terminal by using the circuit provided by various embodiments of the present invention. | 06-05-2014 |
20140152288 | Reference Voltage Generator and Corresponding Integrated Circuit - The present invention provides a reference voltage generator and a corresponding integrated circuit. The reference voltage generator comprises: a current mirror connected between an input voltage and ground and comprising a source current branch and a mirror current branch; a resistive element connected in series in the source current branch; and a voltage stabilizing element connected in series in the mirror current branch, wherein the mirror current generated in the mirror current branch is operable to meet working current requirements of the voltage stabilizing element, and one terminal of the voltage stabilizing element serves as a reference voltage output terminal Regarding application of an input voltage having a larger change scope, embodiments of the present invention provide a current having a smaller change scope and a lower power consumption so as to facilitate operation of high-voltage and low-power consumption integrated circuit, and particularly exhibit advantages in applications requiring a smaller current during a standby period. | 06-05-2014 |