System-level hardware designers pay careful attention to selecting the right analog signal path ICs for their specific applications. Each IC needs “clean” power but often, power management is the last part of a system design. As many designers know, power supply design affects the analog signal integrity which, ultimately, impacts overall system performance.
National Semiconductor’s broad portfolio of low-noise, low dropout (LDO) regulators preserve signal fidelity in the analog signal path over a wide range of input voltages and output currents. National’s portfolio of low-noise LDOs provide maximum Power Supply Rejection Ratio (PSRR) and low output voltage noise for low-power, space-constrained applications. In contrast to switching regulators which induce a voltage ripple and other high frequency voltage spikes in their output, an LDO’s PSRR filters out unwanted noise.
Low Dropout Regulators Deliver Quiet Power for Noise-Sensitive Circuits - [Link]
An unconventional, scalable high efficiency 12V solar power system, a battery charge controller with low voltage cutout to protect the battery. www.opend.co.za writes:
Low idling current
This circuit was designed for small to medium lead acid systems and feature a lowish idle current ( 5mA ) which increases battery life on small capacity systems.
Easily obtainable parts
All the parts in this design are through hole parts and can be found from a number of sources. None of the parts need programing and only a voltmeter and an adjustable supply is needed to calibrate the board. This makes it easy and cheap to build and maintain.
This is the 3rd iteration of the design, with improvements and bug fixes at every step.
A Novel high efficiency scalable solar regulator - [Link]
The LM25117 is a synchronous buck controller intended for step-down regulator applications from a high voltage or widely varying input supply. The control method is based upon current mode control utilizing an emulated current ramp. Current mode control provides inherent line feed-forward, cycle-by-cycle current limiting and ease of loop compensation. The use of an emulated control ramp reduces noise sensitivity of the pulse-width modulation circuit, allowing reliable control of very small duty cycles necessary in high input voltage applications.
LM5117 / LM25117 — Powerwise Wide Input Range Synchronous Buck Controller with Analog Current Monitor - [Link]
This device, remember, takes 80-265Vrms wall power and puts out a (relatively) clean 5V DC. According to the datasheet, the way this thing works is by monitoring the voltage of the AC waveform and charging a big electrolytic capacitor during the low voltage segments on the leading and trailing edge of the (half-rectified) wave. The controller then discharges the capacitor to sustain the 5V DC. It claims it can handle a maximum load of 35mA
Be careful working with unisolated AC voltage, that stuff will kill you in an instant. We don’t do it.
FSAR001 AC to 5volt DC regulator – [Link]
Pin-compatible regulator with high efficiency for fixed voltage [via]
For decades, the linear voltage regulator of the 78 series and its variants have been extremely popular, because these three-legged ICs allow stable supply voltages in the low voltage range to be created in a cost effective way. However if the difference between input and output voltage is considerable, efficiency decreases and the wasted heat must be dissipated which is not only costly and space consuming, but also a source of problems with thermal drift in sensitive and precision electronics. The use of switching regulators on the other hand generally requires more external parts and greater board surface. A modern replacement for the popular 3-pin voltage regulator would therefore make life easier for many electronic designers and engineers.
K78XX = switch-mode LM78XX – [Link]
McZ writes in with an impressive step-down regulator: [via]
The TPS56221 is a high-efficiency synchronous switcher with integrated FETs, which achieves a power density of greater than 200W/in3 with greater than 90 percent efficiency at high loads. The easy-to-use SWIFT step-down regulator supports 25-A point-of-load designs for telecommunications, networking and other applications.
25A 14V step-down regulator with integrated FETs - [Link]
Using an Atmel ATmega, this project is able to regulate how much power an AC device (Lamp/Fan) receives from the wall. The project write-up is extremely detailed with all schematics and software freely available to look at and for download.
Remote Controlled AV Regulator – [Link]
How to get 5 volts from a higher voltage? Of course by LM7805.
The fact that the chip is the LM7805 linear voltage regulator. This means that all the excess stress she planted on his. That is, when an input voltage of 12 V, she is forced to provide for themselves a voltage drop of 7 volts. Multiply that by at least a current of 100 mA, and already get 0.7 W power dissipation. With a little high currents or the difference between input and output voltage without heat sink is not enough.
Step-down switching regulator – [Link]
Adam introduces the LM21212-1 & LM21215 12-15A High Efficiency, Adjustable Current Synchronous Switching Regulator family, which features:
- Greater than 97% peak efficiency
- 2.95 – 5.5V input voltage range
- Resistor-programmable current (LM21215)
- Synchronous or adjustable frequency up to 1.5 MHz (LM21212-1)
- Start up into pre-biased loads
- Sub-7mΩ integrated FETs
- Output voltage tracking capability
LM21212/15 15A Adjustable Current Buck Regulator – [Link]
This device allows solar cell arrays to be connected to either conventional lead-acid, sealed lead-acid, or lithium storage batteries without fear of overcharging. It allows two different electrical loads to be driven from the batteries at two different charge states to maximise power usage efficiency.
Photovoltaic Solar Battery Regulator and Load Controller – [Link]