US 11,720,129 B2
Voltage regulation system resistant to load changes and method thereof
Chia-Liang (Leon) Lin, Fremont, CA (US)
Assigned to REALTEK SEMICONDUCTOR CORP., Hsinchu (TW)
Filed by Realtek Semiconductor Corp., Hsinchu (TW)
Filed on Apr. 27, 2020, as Appl. No. 16/858,830.
Prior Publication US 2021/0333813 A1, Oct. 28, 2021
Int. Cl. G05F 1/575 (2006.01); G05F 3/24 (2006.01)
CPC G05F 1/575 (2013.01) [G05F 3/24 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A system comprising:
a voltage regulator configured to receive a first reference voltage and output a regulated voltage;
a bias voltage generator comprising a diode-connect transistor and a resistor connected in series configured to receive a bias current and output a reference gate voltage; and
a plurality of switch-load circuits, each of said plurality of switch-load circuits comprising a common-drain transistor configured to receive power from the regulated voltage, receive control from the reference gate voltage via a switch controlled by a logical signal, and output a supply voltage to a load shunt with a decoupling capacitor, wherein a size of the common-drain transistor is scaled from a size of the diode-connect transistor in accordance with a ratio between a current of the load and the bias current, wherein:
the diode-connect transistor and the resistor connected in series establish a bias voltage equal to a threshold voltage of the diode-connect transistor plus an over-drive voltage of the diode-connect transistor plus a product of the bias current and a resistance of the resistor,
the bias voltage reference generator further comprising a low-pass filter configured to filter the bias voltage into the reference gate voltage, and
a length of the common-drain transistor is equal to a length of the diode-connect transistor, a width of the common-drain transistor is equal to a width of the diode-connect transistor times the ratio between the current of the load and the bias current.