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Design of DC Power Supply and Power Management
Published in Nihal Kularatna, Electronic Circuit Design, 2017
For the simple cases of single- or dual-rail power requirements, there is a choice of three-terminal linear regulator chips; these are low cost and easy to implement, with excellent noise and drift characteristics. The most useful property is their speed of response to transient loads. The only major disadvantage of these solutions is their low efficiencies, which in general range between 30% and 50%. There are ways to improve the efficiencies of linear regulators by manipulating the rectifier circuits in the input stages using silicon-controlled rectifiers [22]. Many common loads can tolerate slower responses and greater amounts of high-frequency noise. For such simple requirements, there are switching regulator solutions where the equivalent of a three-terminal linear IC solution is provided by integrated switching regulator (ISR) techniques by companies such as Power Trends. ISRs are able to provide buck, boost, or inverting voltage values from a single DC bus supply such as 5 V [23]. Figure 3.8 indicates a DPA solution based on an intermediate bus architecture (IBA) of 5 V. Another fully packaged switching solution for high-current-capability DC rails is the “brick converter,” where a wide range of voltages (0.9 V to 48 V) is possible at currents up to a few tens of amperes [24,25]. Figure 3.9 shows the relative sizes of quarter, eighth, and sixteenth brick sizes.
Diodes and power supplies
Published in David Crecraft, David Gorham, electronics, 2018
The simplest and most common method to achieve voltage regulation is by adding a device called a linear voltage regulator, an IC containing all the circuitry necessary to implement the control function outlined in Fig. 8.11. The word ‘linear’ implies that this is an analogue device which works by continuously adjusting the output current to maintain a constant output voltage, rather than by the ‘switching’ principle which is described in the next section. A wide variety of linear regulator ICs is available, both for fixed voltages (such as ± 3 V or ± 5 V for logic circuits, or ± 12 V for op amp circuits), or variable types which use external resistors to set the output level.
Power Management IC Design for Efficient DVFS-Enabled On-Chip Operations
Published in Iniewski Krzysztof, Integrated Microsystems, 2017
Driven by perpetual improvements in efficiency and quality of regulation, modern power ICs have undergone several transitions and considerable development. Early power supply designs involved the application of linear regulators to provide a single steady supply voltage. Linear regulators are active linear analog circuits that are used to convert an unstable and noisy DC power source into a well-regulated power output. This is achieved through a simple and low-cost design that is not associated with any magnetic components, making them very desirable for certain noise-sensitive applications. Some popular linear regulator topologies include the standard linear regulator and the low-dropout (LDO) regulator, as illustrated in Figure 2.2. The dropout voltage here refers to the minimum voltage drop required across the linear regulator between input and output voltages to maintain valid output voltage regulation. The fundamental structure of a linear regulator consists of an error amplifier (EA) and a pass power transistor, which operates as a voltage-controlled current source. The EA continuously monitors the output voltage against a bandgap voltage reference. Based on the regulation error, the amount of current delivered to the load is controlled, in order to maintain the output voltage at the desired value. Irrespective of their advantages, the major drawback of linear regulators lies in their topological limitations. Only step-down voltage conversion can be achieved. In the meantime, the efficiency of a linear regulator is highly determined by the dropout voltage. High efficiency is achieved at a low dropout voltage, but drops significantly for higher dropout values. Frequency compensation on such a circuit could be sophisticated and noise/process variation sensitive. Therefore, this type of regulator is not the most efficient hardware implementation for a DVFS-enabled environment, where the ability to provide a large dynamic range of voltages and frequencies is highly preferred.
Single-chip DC–DC buck converter design based on PWM with high-efficiency in light load
Published in International Journal of Electronics Letters, 2023
Chua-Chin Wang, Oliver Lexter July A. Jose, Pang-Yen Lou, Chung-Jye Hsu, Lean Karlo S. Tolentino, Ralph Gerard B. Sangalang
Two of the most popular types of voltage converters are ‘Switching Mode Power Supply (SMPS)’ type (Whittington et al., 1992) (Mahmud et al., 2018) and ‘Low Drop-Out Linear Regulator (LDO)’ type (Rinc´on-Mora & Allen, 1998; Crepaldi et al., 2010). Traditionally, two SMPS methods have been reported to achieve the controller mechanism, i.e. ‘Pulse-Frequency Modulator (PFM)’ and ‘Pulse-Width Modulator (PWM)’ (Chen et al., 2017; Wang et al., 2011).