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: 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.

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 digital phase lock loop circuit provides an output with reduced jitter. The digital phase lock loop circuit includes a phase frequency detector that determines a phase difference between a feedback signal and a reference frequency signal to generate an error signal indicative of the phase difference. A numerically controlled oscillator generates a first oscillator output signal with a frequency proportional to the error signal and a second oscillator output signal indicative of jitter of the first oscillator output signal in reference to the reference frequency signal. A phase accuracy extender determines a delay amount from the second oscillator output signal and delays the first oscillator output signal by the delay amount to generate a phase-enhanced output signal with edges aligned with one of a plurality of reference clock signals.

Abstract: A switching regulator comprises a PWM controller that controls switching of a power converter via a PWM control signal. The switching regulator detects load transients in the load driven by the power converter. Responsive to the detection of a load transient, the switching regulator resets a PWM clock synchronously with a fast clock operating at a higher frequency than the PWM clock. By doing so, the switching regulator beneficially responds more quickly to changes in the load than with conventional architectures that utilize only the slower PWM clock. This provides improved transient response without sacrificing power efficiency.

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: Adaptive multi-mode digital control schemes that improve the light-load efficiency (and thus the overall average efficiency) in switch-mode power converters without causing performance issues such as audible noises or excessive voltage ripples. Embodiments include a switch-mode power converter that reduces current in the power converter using a second pulse-width-modulation (PWM) mode before reaching switching frequencies that generate audible noises. As the load across the output of the power converter is reduced, the power converter transitions from a first PWM mode in high load conditions to a first pulse-frequency-modulation (PFM) mode, then to a second PWM mode, and finally to a second PFM mode. During the second PFM mode, the switching frequency is dropped to audible frequency levels. Current in the power converter, however, is reduced in the second PWM mode before transitioning to the second PFM mode.

Abstract: A switching power converter (200, 300, 400, 500) comprises a transformer (211) with a parasitic capacitance (212), a first switch (207) coupled to the transformer (211) and configured to couple or decouple a load (219) to or from a power source via the transformer (211), a switch controller (205) coupled to the first switch (207) and configured to generate a switch drive signal (206) for turning on or off the first switch (207) according to switching cycles, and a bypass circuit configured to provide a bypass path for the parasitic elements such as the parasitic capacitance (212). The bypass circuit may be coupled in parallel with the auxiliary winding (220), the primary winding (213), or the secondary winding (214) of the transformer (211). High frequency ringing and EMI/RFI is reduced when the bypass circuit is enabled.

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 system and a method that uses primary side sensing to regulate the output voltage at a cable end without any remote sensing of cable connections back from the load. This is accomplished by approximating the current from the control voltage in the control loop through the relationship that defines the Ton time in terms of the control voltage Vc. Once the approximation of the output current is known, it is multiplied by a known fixed cable resistance, and this value is subtracted from the feedback sensor output before it is subtracted from the digital reference. This forces the regulator to raise the output voltage by the amount of drop across the cable, causing the output of the cable to be maintained at the targeted regulation point.

Abstract: A hybrid constant current control system that uses both pulse width modulation (PWM) and pulse frequency modulation (PFM) control. When transitioning from constant voltage mode to constant current mode the present invention can continue to control using PWM. Thereafter, when the voltage has dropped, the present invention smoothly transitions to PFM mode. The point of transition is based upon the switching frequency and the lowest rated voltage of operation. The system and method avoids very short (narrow) Ton times which ensures accurate constant current (CC) control with bipolar junction transistor (BJT) devices. The present invention also avoids acoustic noise because the switching frequency is maintained at a high enough level to avoid such acoustic noise even when the energy transferred through the transformer is still substantial and the output voltage is not too low.

Abstract: A synchronous rectifier circuit rectifies an AC input voltage to produce a DC output voltage. The synchronous rectifier circuit comprises MOSFET switches coupled within the secondary transformer windings resulting in a shortened AC current path compared to conventional synchronous rectifier circuits. The shortened current path mitigates skin and proximity effects, substantially improving the power efficiency of the synchronous rectifier circuit. A rectifier assembly integrates one or more synchronous rectifier circuit within a magnetic core.

Abstract: The power converter includes a transformer that is coupled or decoupled from a power source by a switch controlled by a switch controller. The transformer includes a first primary winding coupled to a secondary winding. The energy stored in the leakage inductance of the first primary winding is received by a second primary winding. The energy received by the second primary winding is provided to the switch controller to power the switch controller. The second primary winding is wound adjacent to the first primary winding to receive more energy from the first primary winding.