Maximising the response performance of power supply ICs

ROHM established QuiCur, a new power supply technology to improve the load transient response characteristics (response performance involving response speed and voltage stability of subsequent stage) of DC-DC converter ICs and LDOs.

The continuing electrification of applications has increased the number of electronic components and design resources needed. There is a growing demand to reduce the number of capacitors employed for various purposes, such as stabilising electronic circuits. What’s more, to decrease the design load for power supply circuits when altering specifications, high-quality power supply ICs that provide excellent response performance and give stable operation are needed.

Generally, power supply ICs constantly monitors the output voltage to ensure stable power supply functionality and includes a feedback circuit that fine-tunes the output voltage by comparing it with an internal reference voltage. Offering a faster response makes it possible to reverse changes in the output voltage created by fluctuations in input voltage and/or load current in a shorter time. On the other hand, shortening the response time may cause the circuit operation to become unstable and the output voltage to oscillate. As the response speed is also affected by output capacitance, until now, it has been challenging to accomplish the desired response performance.

Including the newly developed high-speed load response technology in power supply ICs makes it possible to achieve the ideal performance without inducing instability in feedback circuits. Not only can the number of external components and mounting area be decreased by minimising the capacitance of the output capacitor needed by the power supply IC, but linear adjustment of the capacitance and output voltage fluctuations (negative constant proportional relationship) is enabled, providing stable operation even when the capacitance increases due to specification changes. This greatly reduces power supply circuit design resources by delivering stable operation with fewer external components.