The Hong Kong University of Science and Technology

Neolith LLC

Other

Microchip Technology Inc.

Tsz Yin Man

Ka Nang Leung

Bruce C Larson

Chi Fan Yung

Sam Tung Tsui

Kwok Tai Philip Mok

Paolo Nora

Man Sun John Chan

Alex Hsu

Philip Kwok Tai Mok

John Man Sun Chan

Chi Yat Leung

A circuit for driving the voltage of a capacitive element between two voltage levels has at least one driver cell with a first pair of switches connected in series between a first terminal of a voltage source and the capacitive element, and a second pair of switches connected in series between a second terminal of the voltage source and the capacitive element. A plurality of non-dissipative elements may be connected in parallel or in series between the first pair of switches and the second pair of switches. Combinations of switches from the driver cells may be activated and deactivated in a defined sequence to provide step-wise transfer of energy to the capacitive element. The defined sequence may have a switching pattern with a voltage change portion arranged to cause a change in an output voltage of the capacitive element driver during application thereof on the capacitive element driver.

Arrangements of non-dissipative elements in non-dissipative element-enabled capacitive element drivers

A circuit for driving the voltage of a capacitive element between two voltage levels has at least one driver cell with a first pair of switches connected in series between a first terminal of a voltage source and the capacitive element, and a second pair of switches connected in series between a second terminal of the voltage source and the capacitive element. One or more non-dissipative elements may be connected between the common node of the first pair of switches and the common node of the second pair of switches. Combinations of switches from the driver cells may be activated and deactivated in a defined sequence to provide step-wise transfer of energy to the capacitive element. In one sequence, switches in a selected driver cell may subtract a specified voltage from an input voltage, bypass the selected driver cell, and add the specified voltage to the input voltage.

Non-dissipative element-enabled capacitive element driving

A switch mode power supply (voltage converter) is adapted as a current-mode control buck regulator for different loading conditions. The voltage converter operates in a continuous conduction mode (CCM) during heavy load conditions using pulse width modulation (PWM). When a zero-current detector determines no inductor current during light load conditions (discontinuous conduction mode (DCM) region), the controller initiates adaptive duty control using pulse frequency modulation (PFM). Adaptive duty estimation circuitry provides controllable energy to charge the power inductor to maintain voltage accuracy and maximize efficiency when in the PFM mode. Using clock synchronization and a single control-loop, smooth transition between PFM, PWM, and bypass modes is automatically performed. Clock synchronization from a master oscillator provides a base for frequency division in different operation modes which gives controllable evenly distributed switching harmonics. An inductor zero-current detector triggers an adaptive estimated duty cycle that is synchronized with the master oscillator.

Enhanced switching regulator topology with adaptive duty control and seamless transition of operating modes

A frequency-hopping pulse-width modulator is disclosed, which facilitates a switching regulator to use smaller-size inductive and capacitive elements, to have an improved power efficiency at light load, as well as predictable spectrum at different load levels. The improved modulator automatically determines the switching frequency of a switching regulator according to the load current delivered by the switching regulator from a number of pre-defined frequencies, which are all multiples of a fundamental frequency. By designing the maximum switching frequency of frequency-hopping pulse-width modulator in the MHz range, a switching regulator is able to use smaller-size inductive and capacitive elements. Light-load efficiency of the switching regulator with the frequency-hopping pulse-width modulator is also greatly improved as switching frequency of such switching regulator is reduced with decreased load current. More importantly, spectrum of a switching regulator with the frequency-hopping pulse-width modulator is as predictable as spectrum of a switching regulator with a conventional pulse-width modulator operated at the fundamental frequency.

Frequency-hopping pulse-width modulator for switching regulators

A low-dropout regulator with a single-transistor-control providing improved transient response and stability is disclosed. The single-transistor-control provides a dynamic resistance at the output of the regulator for minimizing undershoot and overshoot, and hence improves transient response. Since the single-control transistor reduces the output resistance of the regulator, the output pole is pushed to a sufficiently high frequency without affecting stability. Therefore, the limited choice of combinations of the output capacitance and its equivalent-series-resistance is substantially relaxed.

Single transistor-control low-dropout regulator

Single-transistor-control low-dropout regulator

Growing community of inventors

Hong Kong, China

Tsz Yin Man