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Power Management
Published in Nihal Kularatna, DC Power Supplies Power Management and Surge Protection for Power Electronic Systems, 2018
Recent generations of charge pumps offer improved specifications and have become a viable DC-DC conversion method for many portable appliances where high-density converters are necessary and circuit area is limited Two common charge pump types are hysteretic and fixed frequency. Figure 6.5a shows the concept of hysteretic control in charge pumps With this technique, an output voltage that falls below the reference voltage enables the oscillator. During the first clock cycle, the bucket capacitor charges to the input voltage. During the next cycle, the total charge, consisting of Cbucket and Cin, transfers to the output capacitor. This cycle repeats until the output voltage reaches the upper hysteretic threshold, at which point the comparator disables the oscillator. The internal comparator continues to enable/disable the charge pump switches based on the output level [10]. The example shown is for an SC1517-5.
High-Efficiency Power Amplifiers
Published in Choi Jung Han, Iniewski Krzysztof, High-Speed and Lower Power Technologies, 2018
Guillermo Velasco-Quesada, Herminio Martínez‑García, Alfonso Conesa-Roca
Their operating principle is simple; the output stage uses PWM, a rail-to-rail output signal with variable duty cycle, to generate the output voltage as in a class-D amplifier. The magnitude of the output voltage is sensed and the supply rails are switched as needed to more efficiently supply the required power. For a low-output voltage swing requirement (below the external supply rail VDD), the output range is between VDD and ground. When output voltage swing above VDD is required, an internal inverting charge-pump circuit generates negative rail (VSS), replacing ground as the lower supply. The high-output voltage swing range is then VDD to VSS, approximately double the low swing range. This approach efficiently manages power consumption by switching the operating rails as needed according to the output voltage swing requirements.
Low-Power RF Digital PLLs with Direct Carrier Modulation
Published in Christopher Siu, Krzysztof Iniewski, IoT and Low-Power Wireless, 2018
Salvatore Levantino, Carlo Samori
The most widely adopted architecture for a frequency synthesiser is the analog charge-pump PLL in Figure 9.4a. Though largely employed in industry for their good performance, analog PLLs do not so easily take advantage of today’s scaled CMOS processes. The charge pump dissipates non-negligible power which cannot be reduced without impairing noise performance and which represents a limit in low-power applications. It also adds non-linearity to the loop, which worsens noise and spur performance. Besides, the analog loop filter may require a relatively large capacitor to be implemented on chip, in the order of nF.
High-temperature LTCC assembly and design of SiC BJT-based negative charge pump
Published in International Journal of Electronics Letters, 2022
Sajib Roy, Khandokar Asif Faruque, Affan Abbasi, Alan Mantooth
Testing of charge-pump circuits at high-temperature levels of 500°C on low temperature co-fired ceramic (LTCC) material has not been shown in any of the abovementioned works of literature. Charge pump circuits are voltage converters with broad applicability in sensor interfacing, gate drivers, and memory circuits requiring dual-power supplies for biasing (Jieh-Tsorng & Chang, 1998). Basic charge pump circuits use capacitor components for energy storage to provide voltage conversion without any inductor component. In this paper, a negative charge pump circuit is designed in the SiC BJT technology. It has been packaged in an LTCC module along with surface-mountable high-temperature ceramic capacitors. A conventional negative charge pump circuit consists of an oscillator, diode-based charge pump core, and a regulator to provide bias to the oscillator (Ker et al., 2006). The charge pump core circuit uses the oscillator output switching signal to generate a stable negative voltage at its output. The charge pump core and oscillator circuit have been described in this paper. The negative charge pump circuit is designed on the LTCC module that allowed high-temperature testing of the circuit inside a thermal oven.
Radio frequency energy harvesting circuits design for the applications of low power electronics
Published in International Journal of Electronics Letters, 2022
Joydeep Banerjee, Subhasish Banerjee
RF signal is normally analog ac signal. A rectifier is required for the conversion of ac to dc signal. The charge pump circuit, such as voltage multiplier (Villard multiplier circuit in this work) followed by a rectifier is used to increase and rectify the input voltage (Vin). The applicable amount of output voltage can be achieved by engaging multiple stages of voltage multiplier. Under load, output voltage also drops due to capacitor charge drain. Charge drained (Δq) by the load current (ILoad) per period at frequency f is associated with this formula as given in Equation (2).
A Single Clock Charge Pump with High Conversion Ratio in 0.18 µm Process
Published in IETE Journal of Research, 2018
N. Sohrabi, M. Dolatshahi, E. Borzabadi
So, higher pumping voltage of the proposed charge pump in comparison with other charge pump circuits makes it more practical for low power supply systems. Although, by adding more pumping stage, the output voltage increases. But there is a trade-off while increasing number of stages. The number of capacitors and mosfets will be increased, which will increase area, loss and production costs.