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Mayell

Robert Mayell, San Francisco, CA US

Patent application numberDescriptionPublished
20080290910METHOD AND APPARATUS FOR A VOLTAGE TRIGGERED CURRENT SINK CIRCUIT - A current sink circuit is disclosed. An apparatus according to aspects of the present invention includes a sensing element, a pass element coupled to the sensing element and a setting element coupled to the pass element. The setting element provides both a voltage threshold level and a current regulation reference. The pass element is to pass current conducted through the current sink circuit in response to the setting element. The current conducted through the current sink circuit is substantially zero when a voltage applied across the current sink circuit is below the voltage threshold level. A signal generated by the sensing element is regulated in response to the current regulation reference by regulating a current conducted through the pass element when a voltage applied across the current sink circuit is above the voltage threshold level.11-27-2008

Robert Mayell, Los Altos, CA US

Patent application numberDescriptionPublished
20130155733GENERATING A FAST RESET-SIGNAL USING A FAULT-PROTECTION LATCH - Methods and apparatuses are disclosed for monitoring an ac input for fault conditions. The ac input may be monitored by a latch-reset that uses the ac input to charge a line detection capacitor. The latch-reset may be configured such that the voltage at one end of the line detection capacitor drops below a line detection threshold voltage when the ac input is removed for longer than an allowable period of time or if the voltage of the ac input falls below an acceptable value. The drop in voltage at the end of the capacitor may cause an electrically coupled transistor to switch, thereby causing a reset-signal to be generated.06-20-2013
20140104887PROGRAMMING OF AN INTEGRATED CIRCUIT ON A MULTI-FUNCTION TERMINAL - Methods and apparatuses for programming a parameter value in an IC (e.g., any power electronic device, such as a controller of a power converter) are disclosed. The parameter can be selected/programmed by selecting a clamp using an external optional (selectively inserted) diode coupled to a multi-function programming terminal. In particular, a controller IC for a power converter can be externally programmed via one or more multiple function terminals during startup of the converter to select between two or more options using the external programming terminal(s). Once programming is complete, internal programming circuitry may be decoupled from the programming terminal and during normal operation the programming terminal may then be used for another function, such as a bypass (BP) terminal to provide a supply voltage to the IC or other required functionalities.04-17-2014

Robert J. Mayell, Los Altos, CA US

Patent application numberDescriptionPublished
20130058136FORWARD CONVERTER TRANSFORMER SATURATION PREVENTION - A saturation prevention circuit includes a first controlled current source, a second controlled current source, an integrating capacitor, and a comparator. The first controlled current source generates a first current that is proportional to an input voltage that is to be applied to a winding of a transformer. The second controlled current source generates a second current that is proportional to a reset voltage that is to be applied to the winding. The capacitor is charged with the first current while the input voltage is applied to the winding of the transformer and discharged with the second current while the reset voltage is applied to the winding. The comparator compares a voltage on the integrating capacitor with a first threshold and generates a first signal to immediately turn off the switch when the voltage on the integrating capacitor reaches the first threshold to limit a magnetic flux in the transformer.03-07-2013
20130194834POWER SYSTEM WITH SHARED CLAMP RESET - An example power supply includes a first power converter, a second power converter, and a shared clamp reset circuit. The first power converter is adapted to convert an input to a first voltage output and includes a first diode and a first transformer having a first primary winding. The second power converter is adapted to convert the input to a second voltage output and includes a second diode and a second transformer having a second primary winding. The shared clamp reset circuit is included in the first power converter and is coupled to the cathode of the first diode. The shared clamp reset circuit also includes a clamp connection that is coupled to the cathode of the second diode. The shared clamp reset circuit is adapted to manage leakage inductance energy within the first transformer and within the second transformer.08-01-2013
20130194835FLYBACK CONVERTER WITH FORWARD CONVERTER RESET CLAMP - A power supply includes a forward converter having a first transformer coupled to an input of the power supply and to a first voltage output. The power supply also includes a separate flyback converter having a second transformer that is coupled to the input and to a second voltage output. A clamp reset circuit is coupled to the first transformer and to the second transformer. The clamp reset circuit includes a capacitor and a voltage limiting element. The voltage limiting element is coupled to prevent energy received at the capacitor from both the power converters from exceeding a threshold. The voltage limiting element limits a voltage on the capacitor.08-01-2013
20130223106ASYMMETRIC SWITCH FORWARD CONVERTER - A switching circuit for use in a power converter includes a first active switch coupled between a first terminal of an input of the power converter and a first terminal of a primary winding of a transformer. A second active switch is coupled between a second terminal of the input and a second terminal of the primary winding. An output capacitance of the first active switch is greater than an output capacitance of the second active switch. A first passive switch is coupled between the second terminal of the primary winding and the first terminal of the input. A second passive switch is coupled between the second terminal of the input and the first terminal of the primary winding. A reverse recovery time of the first passive switch is greater than a reverse recovery time of the second passive switch.08-29-2013
20140022825METHOD AND APPARATUS TO SELECT A PARAMETER/MODE BASED ON A MEASUREMENT DURING AN INITIALIZATION PERIOD - A power supply control circuit includes a threshold detection circuit coupled to a first terminal to measure a signal at the first terminal during a duration of an initialization period after a fourth terminal has been charged to a supply threshold value. A regulator circuit is coupled between a second terminal and the fourth terminal to charge the fourth terminal to the supply threshold value during the initialization period of the power supply control circuit. A selection circuit is coupled to the threshold detection circuit to select a parameter/mode in response to the signal measured at the first terminal. The first terminal is further coupled to receive one or more additional signals during normal operation at times other than the initialization period to provide at least one additional function for the power supply control circuit after the initialization period is complete.01-23-2014
20140098571SATURATION PREVENTION IN AN ENERGY TRANSFER ELEMENT OF A POWER CONVERTER - A controller for use in a power converter includes logic circuits to turn on and off a switch to regulate an output quantity. A first integrating capacitor is charged with a combination of a first current and a second current while the switch is turned on. The first current is proportional to a reset voltage and the second current is proportional to an input voltage. A reference generation circuit including a second integrating capacitor is charged with the first current during a previous switching cycle of the switch. The reference generation circuit generates a reference voltage in response to the second integrating capacitor. A comparator provides a stop signal to the logic circuits to turn off the switch in response to a comparison of a voltage across the first integrating capacitor with the reference voltage.04-10-2014
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