Built-in miniature mobile multimedia device batteries usually have a small container, and, as a rule, designed for playback recordings for a period of not more than several tens of hours while turned off the display panel or the hours of video playback or a few hours reading e-books.
If the wall outlet is not available or because of bad weather or other reasons the power supply is disconnected for a long time, various mobile devices with colour displays have to feed from the built-in sources of energy. Considering such devices consume considerable current, the batteries can be discharged to the moment when it becomes available electricity from the network the wall outlet.
If you do not wish to plunge into a primeval silence and peace of mind, to power handheld devices can provide backup offline the source of energy that will help out during a long journey in the wild nature and man-made or natural disasters, when your town the item can be a few days or weeks without electricity.
The device which is schematically shown in Fig. 1, is a a relatively strong linear voltage regulator compensation type low saturation voltage and very low intrinsic current consumption. In as a source of energy for this stabilizer can be battery battery cells, battery, and solar battery or manual generator.
Consumed by the regulator current when the load is switched off approximately 180 µa at power supply input voltage 6 V or 210 μa at a voltage of 9 V. the Minimum difference between input and output voltage less than 0.2 In the current a load of 1 A. This is significantly less than that of the best integrated stabilizers from series IRU1010 1209. When the input supply voltage from 5.5 to 15 In the output voltage does not vary by more than 10 mV at load current of 250 mA. When the load current from zero to 1 And the output voltage does not change more than 100 mV when the input voltage is 6 V and not more than 20 mV at the input voltage of 9 V.
When contacts SA1 on the voltage regulator receives voltage power.
Resetable fuse FU1 protects the regulator and the battery power overload. Obetovannye diode VD1 protects your device from reverse polarity voltage litany.
If you increase the voltage, the output voltage also tends to widen.
To maintain a stable output voltage, is used regulatory the site, assembled on VT1, VT4 as a source of reference voltage applied super bright blue led glow HL1. once performing the functions of a Micropower voltage regulator diode, is an indicator of the presence the output voltage.
When the output voltage tends to increase, the current through HL1 increases, also increases the current through the emitter junction VT4, and the transistor opens stronger also stronger opens VT1, which bypasses the gate-source powerful field-effect transistor VT3.
As a result, the resistance of the open channel field-effect transistor increases (since reduced voltage gate-source) voltage across the load decreases.
A trimming resistor R5 to regulate the output voltage, which for charge mobile devices via USB cord must be within 5,0 5,3...V. The capacitor C2 is designed to suppress the excitation of the stabilizer when the increase of the load current. Capacitors C1 and C3 - locking on the supply lines. The transistor VT2 is included as Micropower voltage reference diode with voltage stabilization 8...9 V.
It is designed to protect against high voltage breakdown insulation shutter VT3. Dangerous for VT3 voltage gate-source may appear at the time of inclusion food or touching of terminals of this transistor.
Design and details. Fixed resistors of any type of small General application. Trimmer - WP1-63M, JS4-1, a miniature multi-turn SDR-39, SP5-2 or similar imported. Oxide capacitors type K50-35 or imported counterparts, nonpolar - K10-17, K10-50, km-5. Diode KDA can be replaced by any of series CD CD CD, CD, part no 1n4001 1N4007 Instead of transistors CTG you can use any similar low reverse current collector, for example, any of series KT3102, CT, SS9014, VS, 2SC1845.
Instead of the transistor CTG will fit any of the series CT, CT, SS9015 US, 2SA992. A powerful n-channel field-effect transistor type IRLZ44 in the case of to-220, has a low threshold voltage of opening the gate-source maximum operating voltage 60 V maximum DC current up to 50 A, the resistance the open channel is 0.028 Ohms. In this design, you can replace the IRLZ44S. IRFL405, IRLL2705, IRLR120N, IRL530NC. IRL530N, set Field-effect transistor on dural or copper heatsink is sufficient for specific options the application of the cooling surface area. When mounting the findings of the field transistor short-circuit provoloki Noah jumper.
Mentioned types of transistors" of the different Pinout and different types of buildings. Superjake led RL30-CB744PV blue glow in round 3 mm case can be replaced by RL50-CB744D (blue, 5 mm), RL30-WH744D (Bay, 3 mm), RL30-UV744D: (purple, 3 mm) RL50-GH744D (green, 3 mm) and other similar direct work voltage of 2.5...3.2 V. Resetable fuse to set the types of MF-R110, MF-S120, LP30-110, LP60-110 and similar. Maybe applying and traditional fuse. Power switch - PCN.
The apparatus may be mounted on the PCB size h mm sketch which is shown in Fig. 2. As a standalone power source can use, for example, four series-connected alkaline galvanic cells with a capacity of 4 Ah.
This option is preferred if you plan to use this design relatively rare. Use high-quality alkaline elements will provide long-term storage battery, and the capacity of one element, for example, 6 A/H will be enough for the battery pocket of the player for at least 130 hours of listening to MP3/WMA phonograms (when consumed current of 45 mA).
If you plan to use this device relatively often or your player draws significantly more current even when display is off, it will be the expedient use rechargeable 6 V battery, for example, sealed motorcycle or large flashlight.
You can use the battery from 5 or 6 pieces series Nickel-cadmium batteries, for example, "Panasonic" type P400D, 4Ah; "Varta" type 5520 (HR20), 5 Ah. Camping, fishing, for recharging batteries and power a handheld device might be useful the use of solar panels, capable of delivering a current of at least 150 mA at the output voltage of 6 V.
When powered player from this stable source of energy should to cityat that the control transistor in the circuit "minus", so simultaneous power to the player and, for example, a small active speaker system is possible only if both devices are connected to the output the stabilizer.
Author: A. L. Butov