Mirco Power Circuits

The current tracer helps locate a defective IC that is loading down the power supply. The tracer amplifies the small voltage drop caused by current flow along a fraction of an inch of PC wiring and drives an ordinary microammeter. Needle-point test probes are used to contatt the edge of a PC trace and to follow the current to determine which branch the current takes. One-half of a dual 741 op amp forms a dc amplifier with ac feedback to prevent oscillations and hum-pickup.....

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The voltage reference circuit described below, is a special implementation of current source LM334. Characterized by a very small temperature coefficient metatholio output voltage and consumes only 10uA room temperature. This current fluctuates by a few uA, when the ambient temperature varies significantly. The positive rate of temperature change LM334 offset by the negative of the contact base emitter transistors has a direct thermal coupling with the integrated. To.....

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The circuit uses a CA3440 BiMOS op amp and CA3086 transistor array. The no-load current from 5-volt supply is 1.5 µ A. ..

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The detector uses three sections of an L144 and a DC4011 type CMOS NAND gate to make a very low power voltage monitor. If the input voltage, Vin, is above Vhigh or below Vlow, the output will be a logical high. If (and only if) the input is between the limits will the output be low..

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Three new linear regulators simplify the design of batteryoperated equipment. The LT®1521 is a 300mA, positive low dropout regulator with micropower quiescent current and shutdown. The LT1175 is a 500mA negative complement with adjustable current limit. A third product, the LT1118, has the unique capability of maintaining output regulation while sourcing or sinking load current...

This 1.5 volt led fasher runs more than a year on a single 'd" cell and alternately flashes 2 LEDs at about a 1 second rate. The circuit employs a 74HC14 CMOS hex inverter that will operate at very low voltages (less than 1 volt). One section is used as a squarewave oscillator (pins 1 and 2), while the others are wired to produce a short 10mS pulse on alternate edges of the square wave so the LEDs will alternate back and forth. The output sections each use a capacitor.....

The LTC®1541 combines a micropower amplifier, comparator and 1.2V reference in an 8-pin package. The part operates from a single 2.5V to 12.6V supply with typical supply current of 5mA. Both op amp and comparator feature a common mode input voltage range that extends from the negative supply to within 1.3V of the positive supply. The op amp output stage swings from rail-to-rail. Figure 1 lists additional features along with a block diagram of the device...

Conventional monolithic micropower op amps with a wide supply voltage range require a large die area and therefore, a large package and footprint. The unconventional LT®6011 dual op amp fits 25mV input precision micropower operation and wide 2.7V to 36V supply range in a tiny new packageits 3mm ½¾ 3mm DFN package is so small it doesnt even have leads. The LT6011 also provides rail-to-rail output swing and utilizes superbeta input transistors to achieve.....

It is always desirable to use a low-battery indicator that consumes as little power as possible. For a 9V, 450-mAhr alkaline battery, a 50-µA low-battery indicator can by itself run the battery down in a little more than a year. Battery-powered devices that need to run continuously for a long time require battery indicators that consume minimal power. The circuit in Figure 1, designed for a 9V battery, uses extra-low power. When the battery is at full charge (9V), the.....

The circuit is powered for years by a single 3 volt lithium battery. It sounds an alarm when the temperature exceeds a certain point. With some minor changes the circuit could also be configured for an under temperature (freeze) alarm. The circuit uses a cheap but accurate thermistor as the temperature sensor...

The CLC505 provides a small-signal bandwidth of 150MHz (Av = +6) while drawing 9mA supply current from ±5V power supplies. Reducing the supply current to 1mA decreases the bandwidth by only a third; 50MHz (Av = +6). Please refer to the CLC505 data sheet for a full performance description over the 1mA to 9mA supply current range. The following application note is intended to supplement the CLC505 data sheet describing its operation with quiescent supply currents at.....

This circuit flashes a power indicator LED to keep the average current low...

This audio amplifier circuit, connected to 32 Ohm impedance mini-earphones, can detect very remote sounds. Useful for theatre, cinema and lecture goers: every word will be clearly heard. You can also listen to your television set at a very low volume, avoiding to bother relatives and neighbors. Even if you have a faultless hearing, you may discover unexpected sounds using this device: a remote bird twittering will seem very close to you...

The LTC®1440 series comparators are true micropower devices. They eliminate current peaking during switching, resulting in greatly reduced power consumption versus frequency, or when the inputs are nearly balanced. Figure 2s plot contrasts the LTC1440s power consumption versus frequency with that of another comparator specified as a micropower component. The LTC1440 has about 200 times lower current consumption at higher frequencies, while maintaining a.....

The LT®1462/LT1464 duals and the LT1463/LT1465 quads are the first micropower op amps to offer picoampere input bias currents and unity-gain stability when driving capacitive loads. For each amplifier, the LT1462/LT1463 consume only 28mA of supply current; the faster LT1464/ LT1465, just 145mA. Low supply current and operation specified at ±5V supplies make these amplifiers appropriate for portable low power applications...

Here are some utility circuits for use with the Ramsey FM10a, and other small FM stereo transmitter kits. This information may be helpful for setting up a micro powered FM radio station. The FM10a and similar kits tend to put out a low quality, broad band output signal. This is not a big problem with a 5-10 milliwatt signal, but amplifying the output of such kits beyond 50mw is a bad idea, as the amplified signal can cause interference with other radio services, drawing.....

The circuit in Figure 1 implements a low-cost, micropower, latching motor controller that uses current sensing rather than switches to stop the motor. The design is optimized for a supply voltage of 3 to 9V, making it well-suited to battery-powered applications. To understand how the circuit works, assume that cross-coupled flip-flops IC1A and IC1B are both in a reset state, such that the D input of each one is high. Because both Q outputs are low, the H-bridge.....

The open cell voltage of a small silver oxide button cell battery remains very close to 1.5 volts over most of the life of the cell. However, there is a relationship between battery health and the internal resistance of the cell. This circuit when used in conjunction with an oscilloscope will measure the internal resistance...

If truly low power oscillators interest you, this circuit draws a mere 2 microwatts (500nA) from a 6v battery. It uses a very inexpensive C-MOS IC to produce a frequency of 2Hz. However, by changing the component values you can push it to 300Hz. The circuit draws much less current than traditional C-MOS oscillators using a Schmitt trigger inverter. It also produces fast leading edges. However, if you need more drive current, a C-MOS buffer should be included...

This circuit is designed to monitor two alkaline cells (3v) that form the battery often used in portable electronic equipment. It use an inexpensive IC from Panasonic that is connected to an efficient LED flashing circuit. When the battery voltage drops below a certain point the circuit flashes the LED. In the off state the circuit draws only 1uA, while in the active flashing state it draws 20uA...