Circuits & Schematics: power supply - 2

11. Simple, low-voltage charge-pumps. Part 2 - Alternatives
    Rod Elliott
    Circuits Beginners Supply Microchip TC7660 TC7660S
    .. and voltages of 5, 12, 15 and 24 V are common. Manufacturers include AimTec, CUI, Mornsun, Murata, Recom and Traco Power, plus innumerable Asian versions (often without a name printed on the case). If you buy these from eBay, be ...
    .. voltage booster is a 'true' charge pump. When the output of the 555 is low, C4 charges from the supply via D1. When the output goes high, the positive end of C4 is forced high (to +24 V in a perfect world), and ...
    Jun 12, 2025

12. Simple, low-voltage charge-pumps. Part 1 - Operating principle
    Rod Elliott
    Circuits Beginners Supply Microchip TC7660 TC7660S
    .. Operation at 5 V is theoretically possible, but the performance will be very poor. Both can be used to 'stack' a power supply, so you could get a +47 V supply 'stacked' on top of a +35 V supply. The same is possible for ...
    .. need for transformers or 'esoteric' parts. The first is a simple charge-pump voltage booster, that will raise your supply voltage by a factor of two - at least in theory. Reality is different, because there are losses in the 555 ...
    Jun 12, 2025

13. A two-wire temperature transmitter using an RTD sensor
    Jayapal Ramalingam
    Circuits Analogue Design Measurement Texas Instruments INA122 LM334 XTR116U CD40106B
    .. A 24-V DC supply is fed from the control room, and the current drawn is proportional to the temperature. Since the power and signal travel in the same pair of wires, this arrangement offers cable savings. In Figure 1’s ...
    Jun 11, 2025
14. Build a simple, soft-action muting switch
    John Firestone
    Circuits Audio ON Semiconductor 2N3819
    .. circuit in Figure 1 adds a soft muting switch with power-up/power-down muting to a line-level audio circuit. R 4 , C 1 , and JFET Q 1 quietly ground a signal in 100 to ...
    .. audio circuits. For this process to work, the signal path should remain stable to below roughly one-third the normal supply voltages below 4 V in this example. Q 1 can then finish muting. Making Q 1 a more tightly defined PN4392 can ...
    Jun 4, 2025
15. Solar power MPPT control Li-ion battery charger
    Manoj Kumar
    Circuits Supply Solar Consonance CN3165
    .. /constant voltage linear charger for single cell Li-ion and Li Polymer batteries. The device contains an on-chip power MOSFET and eliminates the need for the external sense resistor and blocking diode. An on-chip adaptive cell can ...
    .. diode. An on-chip adaptive cell can adjust charging current automatically based on the output capability of input power supply, so CN3165 is ideally suited for solar powered systems. Thermal feedback regulates the charge current to ...
    Jun 4, 2025
16. Revisited: Three discretes suffice to interface PWM to switching regulators
    Stephen Woodward
    Circuits Supply Microcontrollers Usage Texas Instruments TPS62933
    .. components: the PWM switch Q1, and the ripple filter capacitors C1 and C2. Note that V OUT will go to for about 6 ms during power up while C1 and C2 are charging, but that should be okay. The C2 capacitance required for 1 lsb (0.4%) PWM ...
    .. on this lengthy number shortly. A cool feature of this simple topology is that, unlike many other schemes for digital power supply control, only the precision of R1, R2, and the regulator’s internal voltage reference matter for ...
    Jun 2, 2025
17. A single op-amp solution to stabilize laser output
    Anirban Chatterjee
    Circuits Laser Microcontrollers Usage Texas Instruments OPA551
    .. are often packaged with a photodiode. The output current from this photodiode can be monitored to regulate the output power intensity of the laser diode. SLDs, however, are prone to pathological drifts, such as temperature variations ...
    May 29, 2025
18. Precision programmable current sink
    Stephen Woodward
    Circuits Analogue Design Supply Diodes TL431
    .. constant sink current of: It also illustrates adding a booster transistor Q1 to accommodate applications needing current or power beyond Z1’s modest TO92ish limits. Notice that Z1’s accuracy will be unimpaired because whatever ...
    .. small digital testing system. Be sure to adequately heatsink Q1. Figure 6. The combined current sink and small system power supply where the max I S is 1 A, Max V S is 20 V, and I S = D. Reference Woodward, Stephen. Cancel PWM DAC ripple ...
    May 22, 2025
19. Another PWM controls a switching voltage regulator
    Christopher Paul
    Circuits Supply Texas Instruments SN74LVC2G14 SN74LVC14A TLV333
    .. (µPs) that can produce a PWM clocked at 20 MHz. However, the supply currents running through that IC’s power supply bonding wires can cause voltage drops. This means that the PWM signals don’t quite swing to the ...
    May 20, 2025
20. Converting square-waves into saw-teeth
    Stephen Woodward
    Circuits Oscillators Texas Instruments CD74HC4053 TLV2371
    .. ramp followed by a quick reset to zero) from digital timing signals is a common function. It usually requires a negative supply as sketched in Figure 1, where Negative current through R1 ramps up inverting integrator A1’s output ...
    May 12, 2025

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