An Integrated Regulated Resonant Switched-Capacitor DC-DC Converter For PoL Applications

rPOL2V5: a compact radiation-hard resonant switched-capacitor DC-DC converter for the CMS HGCAL

“…To achieve output voltage regulation, the controller tunes the phase shift between PWMH and PWML, which in turn leads to a change in the switching frequency of the converter in the range 200 kHz -10 MHz. In order to achieve output voltage regulation for a wide range of conversion ratios and to boost the light-load efficiency, the controller uses different modes of operation (more details are presented in [2,9]). Due to the pulsed nature of the currents flowing in the input and output of the converter, at each switching cycle the parasitic inductances associated to the 𝑉 𝑖𝑛 − 𝐺 𝑁 𝐷 and 𝑉 𝑜𝑢𝑡 − 𝐺 𝑁 𝐷 paths (see Figure 1a) experience large current variations, 𝑑𝐼 𝑑𝑡 , thus generating large voltage spikes on the power transistors.…”

“…The first prototype of rPOL2V5 proved the effectiveness of its novel multi-mode control strategy and the tolerance of the converter to a TID of 220 Mrad [2,8,9]. Those studies revealed that the initial version of the rPOL2V5 did not always operate reliably and it had a sub-optimal efficiency in certain operating conditions.…”

“…It is a second-stage converter that steps down the voltage from 2.5 V to an adjustable output voltage in the range 1-1.5 V, providing a maximum output current that depends on the output voltage value, in the range 2-5 A. The converter's module hosts an ASIC designed using 130 nm CMOS (which includes the power switches and the control circuitry) and discrete components such as capacitors and inductors [2].…”

2.5V step-down DCDCs: a radiation-hard solution for power conversion

“…This allows the tank to generate the proper current, while keeping a constant Vout. The novel controller developed for rPOL2V5 implements different operation modes that optimize the efficiency for the full range of load currents [5]. In particular, the mode used at heavy loads is inherently inefficient for light loads, where two alternative modes can be used: on one hand, the light load operation provides the best efficiency and the smallest output ripple, but it is not functional for Vout>Vin/2.…”