A Digital LDO Employing A Switched-Capacitor Resistance
It uses a switched-capacitor resistor instead of an array of switches, which allows it to implement a voltage divider between its resistance and the effective resistance of the load to regulate the load voltage precisely, even under low supply voltages.
It is a digital low dropout (LDO) linear regulator, which regulates the voltage of a digital supply, regardless of load current or input voltage changes. It can operate any digital circuit, including processors, digital basebands in wireless modems.
Researchers at UC San Diego have invented a novel digital low dropout (LDO) linear regulator, which regulates the voltage of a digital supply, regardless of load current or input voltage changes. Unlike analog LDOs, digital LDOs are more amenable to deeply scaled CMOS technologies, and can operate more easily at low supply voltages. Compared to existing DLDOs, the proposed concept does NOT use an array of switches (which could be linearly or binary weighted) to form a digitally-controllable resistance, but instead uses a switched-capacitor resistor. In this way, the resistance of the LDO output is not set by how many switches are on, which requires a complex control network, but instead, based on the switching frequency of the circuit. This makes for a simple, non-linear, hysteretic control loop that responds to load or input variations within a single clock cycle - the fastest possible response time of a DLDO. In addition, precise frequency control, in this case set via an implicit relaxation oscillator, enables far better regulation accuracy than prior-art DLDOs.
State Of Development Working prototype chip fabricated and measured. Intellectual Property Info A provisional patent has been submitted and the technology is available for licensing. Related Materials Tech ID/UC Case 29200/2018-220-0 Related Cases 2018-220-0
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