Patent application number | Description | Published |
20080278872 | Electrostatic Discharge Protection Circuit - Techniques pertaining to designs of ElectroStatic Discharge (ESD) protection circuits are disclosed. In one embodiment, an ESD protection circuit combines a substrate-driving technique with a gate-driving technique to ease the ESD design and save the silicon area. In another embodiment, an ESD protection circuit is based on a Positive Metal Oxide Semiconductor field effect transistor (PMOS) in a standard Complementary Metal Oxide Semiconductor (CMOS) process. In another embodiment, the ESD protection circuit is based on a negative Metal Oxide Semiconductor field effect transistor (NMOS) in the standard CMOS process. Depending on implementation, the ESD protection circuit is implemented for a negative voltage input pin, a normal input pin, and a power supply clamp circuit. | 11-13-2008 |
20080284394 | Low dropout voltage regulator with improved voltage controlled current source - Techniques pertaining to designs of a compensation voltage controlled current source (VCCS) used in low dropout voltage regulators are disclosed. According to one aspect of the present invention, a compensation voltage controlled current source (VCCS) is so designed to meet the low input/output voltage requirements. Various features of the VCCS are demonstrated through several embodiments. | 11-20-2008 |
20080284395 | Low Dropout Voltage regulator - Techniques pertaining designs of LDO voltage regulators are described. According to one design, the LDO voltage regulator comprises: a differential amplifier circuit having a pair of input terminals and an output terminal, one of the input terminals coupled to a predetermined reference voltage; an intermediate amplifier circuit having an output terminal and an input terminal coupled to the output terminal of the differential amplifier circuit; and an output pass circuit comprising a pass transistor, an output resistor and an output capacitor, the pass transistor having a control terminal coupled to the output terminal of the intermediate amplifier circuit, an input terminal coupled to a power supply and an output terminal coupled to one terminal of the output resistor, the other terminal of the output resistor taken as a voltage output node, the output capacitor coupled between the voltage output node and a ground reference; a feedback circuit including a pair of ladder resistors coupled in series between the voltage output node and the ground reference, a node between the ladder resistors coupled to the other one of the input terminals of the differential amplifier circuit; and a voltage controlled current source circuit having an input terminal coupled to a node between the pass transistor and the output resistor of the output pass circuit and an output terminal coupled to the node between the ladder resistors. | 11-20-2008 |
20090128107 | Low Dropout Voltage Regulator - Improved designs of an LDO voltage regulator with ultra low quiescent current are disclosed. According to one embodiment, an LDO voltage regulator is designed to completely cancel an intermediate gain stage while decreasing a quiescent current and to stabilize a loop circuit by means of two zeros introduced in a frequency transfer function thereof. Such a LDO voltage regulator does not increase the power consumption and applicable in many circuits used in electronic devices. | 05-21-2009 |
20090167197 | Driver and method for driving LEDS on multiple branch circuits - Techniques pertaining to driving LEDs on multiple branches of a circuit are disclosed. According to one aspect of the present invention, an LED drive circuit includes a boost circuit configured for receiving an input voltage and providing an output voltage according to a control signal, a selector configured for alternatively selecting one of the feedback signals as an output feedback signal and switching on a corresponding branch circuit, and a pulse-width modulation (PWM) controller configured for generating a pulse-width modulation signal as the control signal for the boost circuit according to the output feedback signal of the selector, essentially to match respective currents in the multiple branches. | 07-02-2009 |
20090167263 | Current limiting circuit and voltage regulator using the same - Techniques pertaining to a voltage regulator with a current limiting circuit having low quiescent current are disclosed. According to one aspect of the present invention, a current limiting circuit is provided for limiting a current passing through an output pass circuit of a voltage regulator, the current limiting circuit comprises: a current sampling circuit for sampling the current passing through the output pass circuit to obtain a duplicated current being proportional to the current passing through the output pass circuit; a current mirror circuit for producing a mirror current being proportional to the duplicated current with the duplicated current as a reference current; a current to voltage converter for producing a voltage being proportional to the mirror current; and a voltage comparator for comparing the voltage produced by the current to voltage converter with a threshold voltage and turning off the output pass circuit when the voltage produced by the current to voltage converter is larger than or equal to the threshold voltage. | 07-02-2009 |
20100264881 | Battery Protection Circuit - A battery protection circuit with quickly testable design is disclosed. According to one embodiment, the battery protection circuit includes a battery voltage detection circuit configured to detect a battery voltage, output an effective trigger signal if the battery voltage reaches a voltage protection threshold, and output an ineffective trigger signal otherwise; a delay circuit configured to receive the trigger signal, output an effective status signal if the trigger signal is maintained effective continuously over a period of time, and outputs an ineffective status signal otherwise; a protection driver configured to receive the trigger signal and the status signal, enter a driving state when both the trigger signal and the status signal are effective, enter a non-driving state when both the trigger signal and the status signal are ineffective, and enter a ready driving state when the trigger signal is effective and the status signal is ineffective. | 10-21-2010 |
20110205191 | ELECTROMAGNETIC SENSING DEVICE HAVING MULTI-POINT TOUCH FUNCTION - An electromagnetic sensing device having a multi-point touch function comprises electromagnetic pens ( | 08-25-2011 |