Wireless communication SoCs, whether BLE, Zigbee, Sigfox, LoRa, or M2M 4G have a duty cycle such that the power consumption in sleep mode dominates the overall current drawn from the battery. For such applications, the design of the “Always-On power domain" (a.k.a AON power domain) is critical.
Minimization of the power consumption of an always-on domain indeed involves paying special attention to the construct of the power regulation network. The selection of the voltage regulator is critical, as it may contribute to more than 50% of the power consumption in sleep mode. The capability of an always-on power domain to operate at very low voltage may significantly lower the power consumption while enabling silicon area and BoM cost savings.
The qLR-Aubrey is a linear regulator with a quiescent current as low as 150 nA, including the reference/bandgap. This voltage regulator supports an input voltage as high as 5.5V (no special process option required) and an output voltage programmable down to 0.55V, i.e. the minimum data retention voltage of RAMs at 55 nm uLP. Embedding a single instantiation of the qLR-Aubrey to supply both the blocks in data retention and the always-on domain saves silicon area and BoM cost while reducing the power consumption of a SoC in sleep mode by up to 80%.
To make such savings achievable, Dolphin Integration provides a complete set of silicon IPs optimized to operate Near Threshold Voltage: standard cell library (SESAME NTV), ultra-low power XTAL and RC oscillators. The Reference schematic (above) is without Dolphin Integration solutions while this digram shows always-on relying on Dolphin Integration Near Threshold Voltage solutions.
Dealing with multiple voltage regulators to supply the same load in different power modes is challenging (risks of short circuits…). Dolphin's RAR, i.e. Retention Alternating Regulator, combines two voltage regulators which operate alternatively: one during SoC active mode(s) – up to 1A – and the other during SoC sleep