Abstract: The embodiments disclosed herein describe the dynamic control of a switching power converter between different operation modes of the switching power converter. In one embodiment, the operation modes of the switching power converter include a switching mode and a linear mode. The switching power converter may be included in a LED lamp system according to one embodiment.

Abstract: A power converter that controls a collector current of a bipolar junction transistor (BJT) by controlling the base current to the BJT after having determined the gain of the BJT. A gain detection block determines a gain of the BJT during a first mode. A current calculation block generates a current setting for the base current based on the gain of the BJT determined by the gain detection block during a second mode distinct from the first mode. In some embodiments, the power converter may be included in a LED lamp system.

Abstract: An improved discontinuous current mode (DCM) switching power converter that compensates for the effect of dead time. The dead time of the switching power converter is measured during a switching cycle and a baseline on-time for a switch of the switching power converter is determined. The dead time and baseline on-time are used in calculating the desired on-time of the switch during a subsequent switching cycle of the power converter. The desired switch on-time regulates the output voltage to a desired voltage level. The desired switch on-time also maintains the average input current to the power converter in proportion to the input voltage, thereby improving the power factor of the switching power.

Abstract: A switching power converter includes a controller configured to transition from a first operating mode to a second operating mode by determining the operating conditions at the transition point between the operation modes. The controller uses a point where a switch included in the power converter would have been turned on if operating under the first operating mode as a reference point to determine when to turn on the switch under the second operating mode. Using the reference point, the switching power converter determines a control period for regulating the switching period of the switch in a second operating mode.

Abstract: A system controls a switching power converter to power LED strings using a predictive feedforward control mechanism. An LED controller determines programmed current levels and duty cycles for driving LED strings. The LED controller determines a predicted load for a subsequent cycle of a switching power converter driving the LED strings based on the programmed current levels and duty cycles. A power conversion controller uses the predicted load information to control switching of the switching power converter. This improves the dynamic response of the switching converter to changing load conditions, thereby improving overall power efficiency and performance of the system.

Abstract: An LED driver controls current through an LED string. The LED driver generates a boosted PWM signal to drive a PWM transistor in the LED current path such that the PWM transistor maintains a substantially constant VGS, thus minimizing turn-on impedance of the PWM transistor. A current mirror circuit controls peak LED current when the PWM transistor is on. A trimming circuit includes a set of programmable switches to couple or decouple trimming transistor from the LED current path, and allowing for fine calibration of the LED current. By maintaining a low resistance and compensating for current mismatch in the LED current path, the LED driver provides efficient power performance and robustness that is particularly beneficial in high current applications.

Abstract: A low-dropout (LDO) voltage regulator includes a switch to generate an output current, and a first sensing module that increases the speed at which the switch is turned off and the output current is decreased in response to detecting a decreasing load current. The LDO regulator further includes a second sensing module that increases the speed at which the switch is turned on and the output current is increased in response to detecting an increasing load current.

Abstract: A controller of a switching power converter employs a dynamically adaptive power supply regulation approach that improves low-load and no-load regulation to achieve ultra-low standby power in a switching power converter. Under ultra-low load conditions when a deep-deep pulse width modulation (DDPWM) is applied, the controller decreases the actual on-time of the power switch of the switching power converter by decreasing the “on” duration of the control signal used to turn on or off the power switch, until the “on” duration of the control signal reaches a minimum value. To further reduce the on-time of the power switch, the controller reduces the power applied to the power switch to turn on the switch more slowly, while maintaining the “on” duration of the control signal at a minimum value. The minimum value of the “on” duration of the control signal and the minimum power applied to the switch are dynamically controlled.

Abstract: A controller of a switching power converter sets an actual turn-on time of a switch in the switching power converter in each switching cycle by selecting one of a plurality of valley points of the output voltage of the switching power converter occurring subsequent to the desired turn-on time of the switch. The desired turn-on time of the switch may be calculated according to the regulation scheme employed by the switching power converter. The controller selects one of the plurality of valley points randomly from switching cycle to switching cycle. The controller generates a control signal to turn on the switching power converter at the selected one of the plurality of valley points of the output voltage occurring subsequent to the desired turn-on time.

Abstract: A controller integrated circuit (IC) for controlling a power converter uses one or more IC pins having plurality of functions such as configuration of a parameter supported by the controller IC and shutdown protection. Several different functions may be supported by a single IC pin, thereby reducing the number of pins required in the controller IC and also reducing the cost of manufacturing the controller IC. The controller IC may also share a comparison circuit among different pins and the different functions provided by those pins. Use of a shared comparison circuit further reduces the cost of manufacturing the controller IC without sacrificing the performance of the IC.

Abstract: The embodiments herein describe a dynamic metal-oxide-semiconductor field-effect transistor (MOSFET) gate driver system architecture and control scheme. The MOSFET gate driver system dynamically adjusts both the gate driver turn-on-resistance and the gate driver turn-off resistance within a single (i.e., one) switching cycle to reduce electromagnetic interference (EMI) in the system and to minimize the conduction loss of a power MOSFET during operation.

Abstract: An adaptive switch mode LED driver provides an intelligent approach to driving multiple strings of LEDs. The LED driver determines an optimal current level for each LED channel from a limited set of allowed currents. The LDO driver then determines a PWM duty cycle for driving the LEDs in each LED channel to provide precise brightness control over the LED channels. Beneficially, the LED driver minimizes the power dissipation in the LDO circuits driving each LED string, while also ensuring that the currents in each LED string are maintained within a limited range. A sample and hold LDO allows PWM control over extreme duty cycles with very fast dynamic response. Furthermore, fault protection circuitry ensures fault-free startup and operation of the LED driver.

Abstract: An LED lamp is provided in which the output light intensity of the LEDs in the LED lamp is adjusted based on the input voltage to the LED lamp. A dimmer control unit detects a type of dimmer switch during a configuration process. Using the detected dimmer type, the dimmer control unit generates control signals appropriate for the detected dimmer type to provide regulated current to the LEDs and to achieve the desired dimming effect. The LED lamp can be a direct replacement of conventional incandescent lamps in typical wiring configurations found in residential and commercial building lighting applications that use conventional dimmer switches.

Abstract: A controller of an AC/DC flyback switching power supply uses adaptive digital control approaches to control the switching operation of a BJT power switch based on primary-side feedback to regulate the secondary-side constant output voltage and output current, without using the input line voltage. Switching-cycle by switching-cycle peak current control and limit are achieved based on the sensed primary-side current rather than the input line voltage in both constant-voltage and constant-current modes, operating in PWM, PFM and/or combinations of a plurality of PWM and PFM modes. The controller IC does not need a separate pin and ADC circuitry for sensing the input line voltage. The controller IC directly drives the BJT base, and dynamically adjusts the BJT base current amplitude cycle by cycle based on load change.

Abstract: A system that provides an intelligent approach to driving multiple strings of LEDs. A processing device determines an optimal current level for each LED string from a limited set of allowed currents. The processing device also determines a PWM duty cycle for driving the LEDs in each LED string to provide precise brightness control over the LED string. The settings for the current level and duty cycle are transmitted to an LED driver for regulating the current and on-off times of the LED strings. Beneficially, the system reduces the size of the LED driver while leveraging existing resources available in the processing device to operate the LEDs in a power efficient manner.

Abstract: A switch controller is disclosed that adaptively controls the operating frequency of a switching power converter in order to improve one-time load response and repetitive dynamic load responses. During a transition from a high load to low load condition, the switch controller clamps the operating frequency of the switching power converter at an intermediate frequency for a period of time before allowing the operating frequency to return to a frequency associated with the low load condition. The clamped frequency is higher than the frequency associated with the low load condition thereby allowing improved response to a subsequent load change to a high load condition. Thus, the system improves dynamic load response without compromising no-load power consumption.

Abstract: An LED lamp is provided in which the output light intensity of the LEDs in the LED lamp is adjusted based on the input voltage to the LED lamp. A dimmer control unit detects a type of dimmer switch during a configuration process. Using the detected dimmer type, the dimmer control unit generates control signals appropriate for the detected dimmer type to provide regulated current to the LEDs and to achieve the desired dimming effect. The LED lamp can be a direct replacement of conventional incandescent lamps in typical wiring configurations found in residential and commercial building lighting applications that use conventional dimmer switches.

Abstract: A switch controller is disclosed that adaptively controls the operating frequency of a switching power converter in order to improve one-time load response and repetitive dynamic load responses. During a transition from a high load to low load condition, the switch controller clamps the operating frequency of the switching power converter at an intermediate frequency for a period of time before allowing the operating frequency to return to a frequency associated with the low load condition. The clamped frequency is higher than the frequency associated with the low load condition thereby allowing improved response to a subsequent load change to a high load condition. Thus, the system improves dynamic load response without compromising no-load power consumption.

Abstract: In a switching power converter, PWM mode and PFM mode are separated into two independent control sections with the control voltage range in each control section determined independently. Each of the PWM and PFM modulation modes cannot operate continuously beyond its boundaries, thereby forming a control gap between the two control sections within which no continuous operation is allowed. In order to supply a load condition within the control gap, the power supply operates at the two boundaries of the control gap. Transition between PWM and PFM modes occurs fast, with low output voltage ripple. No limitation needs to be imposed on the control voltage range in each of the PWM and PFM control sections, because the control parameters in the PWM and PFM control sections need not be matched to one another, due to separation of the PWM and PFM modes by the control gap.

Abstract: A switching power converter detects low load conditions based on the ratio of a first peak current value for peak current switching in constant voltage regulation mode to a second peak current value for peak current switching in constant current regulation mode. The power supply load is considered to have a low load if the ratio is lower than a predetermined threshold. Once a low load condition is detected, the switching frequency of the switching power converter is reduced to a level that minimizes switching loss in the power converter. In addition, the switching power converter also adjusts the switching frequency according to the sensed input line voltage. An offset is added to the switching period to reduce the switching frequency of the switching power converter, as the input line voltage is increased.