Microchip Technology Inc.

Alex Hsu

Paolo Nora

Sam Tung Tsui

Tsz Yin Man

Various embodiments relate to a voltage converter including a control unit configured for operating in a hysteretic control mode. A control unit may be configured to receive a PWM signal, a duty cycle signal, at least one reference voltage, a factor of an output voltage of the voltage converter, and a factor of an input voltage of the voltage converter. The control unit may also be configured to compare the at least one reference voltage to the factor of the output voltage and the factor of the input voltage. Further, the control unit may be configured to generate a first control signal mirroring the PWM signal in response to at least one of: the factor of the input voltage being greater than the at least one reference voltage and the factor of the output voltage being greater than the at least one reference voltage. The control unit may also be configured to generate a second, different control signal including a low logic signal in response to the factor of the input voltage being less than or equal to the at least one reference voltage.

Voltage converters with hysteretic control

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.

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Hong Kong, China

Alex Hsu