LED Driver Circuit Using CAT3603

CAT3603 is a three channel charge pump LED driver IC from Catalyst Semiconductors that can be operated in either LDO mode or fractional mode. The IC can deliver 30mA per channel and can be operated from an input voltage range of 3 to 5.5V DC. CAT3063 has a quiescent current as low as 0.1uA and this makes it suitable for battery powered applications. The operating frequency is 1Mhz which makes it possible to use small capacitors.

LED Driver Circuit Diagram Using CAT3603

Another features are soft start, current limiting, high efficiency (90%) and short circuit protection. Applications of this IC are hand held devices, LCD back lights , LED lighting gadgets etc. The output current can be programmed using an external resistor connected between the RSET (pin 4) and ground.

Charge pump:

Charge pump is a DC to DC converter circuit that uses capacitors as the energy storage component for creating an output voltage that is either higher or lower than the input voltage. A switching circuit (using BJTs or MOSFETs) is used for connecting and disconnecting the voltages from the storage capacitor.

The switching frequency is usually in the kilo or MHz range. The output voltage will be a pulsed one and it is smoothed using an output filter capacitor. Charge pump circuits can double, triple, quadruple, multiply or scale any given voltage. In theory, a charge pump can generate any desired voltage.

CAT3063 LED driver circuit.

The circuit diagram of a three channel LED driver circuit using CAT3063 is shown below (Fig 1). C4 is an input filter capacitor. R1 is the resistor used for programming the output current. C3 is the output filter capacitor. C1 and C2 are the storage capacitors of the internal charge pump circuit. A logic high at pin 5 will enable the IC and a logic low on the same pin will drive the IC into shutdown mode.

In the shutdown mode, the quiescent current is almost equal to zero. With the used value of R1, the LED current per channel will be 25mA. When powered up the CAT6063 operates in 1X mode i.e, the output voltage will be equal to the input voltage. If this output voltage is enough to regulate the current through all LEDs, the IC remains 1X mode.

If the output voltage is not sufficient enough to regulate the desired current through the LEDs, the device automatically switches to the 1.5X mode where the output voltage is 1.5 times the input voltage. This process is repeated when ever the IC is powered up or awaken from shutdown mode.

Selection of R1 is shown in the table below.

LED current (mA)	R1 (kilo ohm)
1	649
5	287
10	102
15	49.9
20	32.4
25	23.7
30	15.4

Notes.

CAT6063 is not suitable for resistive loads.
Unused LED output channels must be connected to Vout pin. They cannot be left floating.
All capacitors are ceramic capacitors.
Dimming of the LEds can be achieved by using a DC voltage for setting the pin4 (RSET) current or by driving the pin5 (EN) using a PWM signal.
There is an exposed pad beneath the IC and it should soldered to the ground plane of the PCB for improved thermal performance.
Supply voltage should not exceed 6V DC.
Total output current should not exceed 120mA.

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Simple Inverter Circuit Diagram

Have you ever wanted to run a TV, stereo or other appliance while on the road or camping? Well, this inverter should solve that problem. It takes 12 VDC and steps it up to 120 VAC. The wattage depends on which tansistors you use for Q1 and Q2, as well as how "big" a transformer you use for T1. The inverter can be constructed to supply anywhere from 1 to 1000 (1 KW) watts.

Simple Inverter Circuit Diagram

Parts:
C1, C2 68 uf, 25 V Tantalum Capacitor
R1, R2 10 Ohm, 5 Watt Resistor
R3, R4 180 Ohm, 1 Watt Resistor
D1, D2 HEP 154 Silicon Diode
Q1, Q2 2N3055 NPN Transistor (see "Notes")
T1 24V, Center Tapped Transformer (see "Notes")
MISC Wire, Case, Receptical (For Output)

Notes:
1. Q1 and Q2, as well as T1, determine how much wattage the inverter can supply. With Q1,Q2=2N3055 and T1= 15 A, the inverter can supply about 300 watts. Larger transformers and more powerful transistors can be substituted for T1, Q1 and Q2 for more power.

2. The easiest and least expensive way to get a large T1 is to re-wind an old microwave transformer. These transformers are rated at about 1KW and are perfect. Go to a local TV repair shop and dig through the dumpster until you get the largest microwave you can find. The bigger the microwave the bigger transformer. Remove the transformer, being careful not to touch the large high voltage capacitor that might still be charged. If you want, you can test the transformer, but they are usually still good. Now, remove the old 2000 V secondary, being careful not to damage the primary. Leave the primary in tact. Now, wind on 12 turns of wire, twist a loop (center tap), and wind on 12 more turns. The guage of the wire will depend on how much current you plan to have the transformer supply. Enamel covered magnet wire works great for this. Now secure the windings with tape. Thats all there is to it. Remember to use high current transistors for Q1 and Q2. The 2N3055s in the parts list can only handle 15 amps each.

3. Remember, when operating at high wattages, this circuit draws huge amounts of current. Dont let your battery go dead :-).

4. Since this project produces 120 VAC, you must include a fuse and build the project in a case.

5. You must use tantalum capacitors for C1 and C2. Regular electrolytics will overheat and explode. And yes, 68uF is the correct value. There are no substitutions.

6. This circuit can be tricky to get going. Differences in transformers, transistors, parts substitutions or anything else not on this page may cause it to not function.

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Build a 12v to 5v DC high efficiency SMPS buck converter using 34063 IC

This project converts 12v DC to a regulated 5v DC at up to 1.8 amps, suitable for driving a tablet computer from a 12v car battery in a power blackout etc.

The circuit for this buck converter is nothing original, basically it is the circuit from the 34063 IC datasheet, and all I did was to use an external PFET instead of the external PNP transistor shown in the datasheet. The external PFET allows currents up to a few amps at good efficiency, however I have used hard current limiting at 1.8A for safety and good performance in this prototype.

Energy conversion efficiency is very high due mainly to the choice of external components used with the cheap 34063 SMPS IC.

 PCB layout.
The prototype was tested in hardware, please excuse the messiness. The layout is far from ideal, I did it this way to allow easy swapping of parts and just to be lazy, to save the effort of making a PCB. However it still works pretty good, and a proper PCB would improve performance a little bit.

PFET choice.
I did not have a lot of PFETs in my parts box so I used a 100v 8A rated part. This was an SMD PFET so I just tacked it on the bottom of the PCB. It is efficient enough to not need a heatsink even at 5v 1.5A continuous output. The PFET I used was not ideal, its "Rds on" value is about 0.3v at 1.5A (0.2 ohms) which is too high and costs efficiency. Going to a 50v >20A PFET with an RDS <0.1 ohms or <0.05 ohms would give a noticable increase in efficiency.

Schottky diode choice.
I used a TO-220 60v dual 10A schottky diode pack (total 20A). This is a no-brainer, although this is overkill these diodes are only $1-$2 and can also be pulled for free from any old PC PSU and most commercial SMPS supplies. Besides the safety of being very large and over-rated, the main benefit is these diodes have a very low forward voltage drop of <0.3v at 1.5A or 2A and this equates to reduced losses (more efficiency).

Inductor choice.
This is just a commercial "3 amp" 24mm total diameter inductor/choke available from hobby suppliers like Altronics Australia. I think it is a 220uH or 330uH value, but sorry I lost the paperwork.  A few other powdered-iron toroid inductors were tried and it is not that critical. It has 51 turns of 1.0mm diameter wire if that helps. The inductor measured 0.32mV at exactly 1A DC, so DC resitance was measured at 32 milliohms.

Schematic and operation.
Sorry for the hand-drawn schematic! As you can see the circuit is minimum parts. It uses just two resitors to drive the PFET from the IC (same as the datasheet), this is not ideal but was done to test the concept and see if a PFET can be driven as easily as the PNP transistor normally is. PFET turnon is good at 0.07uS, but turnoff is not great taking 0.8uS. This costs about 1-2% efficiency. The 560 ohm resistor could be reduced to speed up the turnoff, but this would increase losses in that resistor so it is a tradeoff.

34063 SMPS IC.
The 34063 IC does all the clever stuff, mainly it regulates voltage at 1.25v on VFB pin5. Because of the 6k8:2k2 voltage divider on the output, this gives very close to 5v, I actually saw about 5.01v-4.99v Vout in testing, very nice.

Max current limit resistor.
The resistor between Vin and pin7 sets the max inductor current limiting, this was set by me to roughly 0.18 ohms to give 1.8A current limiting. (Imax = 0.32v / R = 0.32v/0.18 = 1.78A). The current limit is best at slightly above the max required current. This gives better safety and also helps stabilise oscillation.

Caps etc.
CT used the datasheet value of 1nF. That gave oscillator value of 26.2kHz measured on pin3 (with no load), however the whole circuit usually operated at 29-33kHz because of the way the regulation works in the IC. The filter caps; 680uF on the input and 1000uF on the output were chosen to be "good enough". Output ripple was approx 25-30mV which is fine.

Measured efficiency!

Vin    Iin   Pin        Vout  Iout   Pout      Eff %    
12.5v  670mA  8.375W     4.99  1.53A  7.63W     91.1%
12.5v  430mA  5.375W     5.00  1.00A  5.00W     93.0%
12.5v  210mA  2.625W     5.00  0.50A  2.50W     95.2%

Note! Readings were taken from meters with only 2 decimal point resolution and were not lab grade accuracy, so there may be a couple of percent error in readings.

Calculating efficiency (at 1.5A output).
The static power losses were seen on the scope and can be calculated;

PFET Rds on period loss = 0.3v / 12.5v = 2.4% loss

DIODE Vf off period loss = 0.28v * 1.53A * 0.56 offduty = 240mW = 2.8% loss

Inductor resistance loss = 1.53A squared * 0.032 ohms = 75mW = 0.9% loss

560 ohm resistor loss = 10.5v squared / 560 * 44% onduty = 87mW = 1.0% loss

Total static losses at 1.53A output = 7.1%
Calculated other (switching) losses = 100% - 91.1% - 7.1% = 1.8%



Scope current L1 inductor (on period) at 5v 1.5 amps.
Above is the on period current through the PFET and L1 inductor. As it is a PFET this is inverted so the pointy bit at the bottom is the max current, the top is zero current. At 1.5A and 32kHz the SMPS is very stable, as switching period is reduced becuase the peaks just hit the 0.32v max current limit set by my choice of 0.18 ohm resistor. (However voltage regulation is still the main regulation).

Duty cycle is about 44%, and current ripple in the inductor is nice and low with inductor current averaging 1.5A (ripple of 0.56A, between 1.22A and 1.78A). The noise spikes I suspect are from from my messy PCB with power and load wires everywhere and scope leads laying around next to the PCB and wiring.

---

Scope current L1 inductor at 5v 1.0 amps.
Same thing but at 1A. Frequency dropped a bit, closer to the 34063 oscillator freq of 26.2kHz, but still (just) triggering on the max current peaks. Current ripple now larger from approx 0.5A to 1.6A (average output 1A). Timing is still 20uS/hdiv but says 40uS on the screen as I had zoomed my h-axis (sorry).



Scope current L1 inductor at 5v 0.5 amps.
Here the L1 current has gone "discontinuous" meaning the L1 current is reduced to zero during the end of the off period, and has to start from 0 amps again during every on period. Typical of the regulation system used in a 34063 IC, the timing will "stutter" as needed to maintain Vout regulation at a steady 5.0v. This does not matter and the 34063 can be quite energy efficiency when "stuttering" in discontinuous mode like this. At less than 0.5 amps the stuttering can become very erratic looking, but this is all normal.



PFET drain/source voltage (main switching waveform).
(The PFET on period is the top of the waveform). Above you can see the PFET turnon (through a 10 ohm resistor) is nice and fast, It was about 0.07uS turnon time. However the turnoff is poor, because the turnoff is from a 560 ohm resistor and is slow at 0.8uS. This costs significant efficiency.

Using an external digital driver (like a 12v CMOS digital buffer/inverter chip?) to drive the PFET would improve turnoff time a lot and increase efficiency, but this was a test of using the simple datasheet example circuit with an external PFET (instead of the suggested external PNP) and as proof of concept it still works well enough.



5v DC output showing voltage ripple.
Because it is a switching regulator there will always be some ripple on the DC output voltage. This is shown when running at 5v 1.5A and the ripple is typical and acceptable enough at 30-35mV.

Improving efficiency.
This circuit was thrown together very quickly to show how to use a cheap common 34063 IC to get a high efficiency supply from 12v->5v DC at 0-1.5A or so. If you want to invest some effort it can be improved further;

1. My PFET is not a good choice, using a better PFET will give an easy 1% more efficiency, and would be the first choice.

2. The inductor is just an ordinary "off the shelf" type. A properly selected inductor or a good core hand wound for best performance could allow lower operating frequency and less current ripple, and maybe less DC ohms, and maybe pick up another 0.5% efficiency or so. (For lower operating freq CT should also be increased to 1.2nF or 1.5nF etc).

3. The PFET turnoff is too slow. Adding a cheap digital buffer IC could pick up 0.8-1.2% efficiency there from reduced switching losses and reduced loss from the 560 ohm resistor.

4. My PCB has very thin long tracks. Using a well designed PCB with thick short tracks for the main current paths might save 30 milliohms and give maybe 0.5% or more efficiency.

Bill of materials.
* 34063 SMPS 8pin IC (Fairchild/ON Semi/AIS etc, ie MC34063A or NCV34063A).
* 8pin IC socket (optional).
* PFET, rated more than double the input voltage and a few times the desired output current, preferably well under 0.1 ohm Rds on.
* Inductor L1 is a powdered iron toroid of 20-30 mm diameter, with thick wire >1.0mm preferred, 3A rated for a 1.5A capable supply. Value in the 150-470uH range, you may need to try a couple of different types. Ideally current ripple will be <50% at full output current.
* Schottky TO-220 dual 10A or dual 16A diode pack. Choose for low forward voltage, most brands are very good, parts can be found in any old PC PSU.
* 470-1000uF 35v electro cap.
* 1000uF 16-25v electro cap (25v will be larger and generally have a longer life).
* CT 1nF 25-50v ceramic or greencap.
* some 1/4W resistors; 560 ohm, 10 ohm, 6k8, 2k2.
* If you need a test load then a large 10W 4.7 ohm resistor will do.

Modifying the circuit for 12v car operation.
This circuit was designed for a car battery, generally 13.8v to 12.0v when running. If used in a car the circuit needs more protection as the Vin might be >15v at times. I would use a 100 ohm resistor instead of the 10 ohm resistor. Also a 13v zener diode across the 560 ohm resistor will add safety for the PFET. A 12v line filter might also be advised, they can be bought from auto stores.

Modifying the circuit for 24v operation.
Use 560 ohms instead of 10 ohms, so it now has two 560 ohm resistors. And again a 13v zener from PFET gate to source pin. With a 24v Vin you should use a higher inductor value and larger inductor core, 470uH and up are recommended.

[b]Modifying the circuit for high output currents.[b]
The circuit is meant for 5v out, 0-1.8A. It will do ok up to 2.5A just by changing the current limit resistor (at 2.5A the resitor should be 0.12 ohms or so).

Currents up to 5 amps or more should be ok, but use a larger inductor core size rated for more than the max amps you need, and again a larger inductor value helps >470uH is good. The diode pack will be fine, but the PFET should be rated for a few times more current than your max current. If needing 5A output I would use a 40-50v 60A TO-220 PFET which are a common size.

Changing output voltage.
Just change the 6k8 resistor, to change the output voltage to something other than 5.0v. Like most SMPS circuits it works best with roughly 2:1 Vin:Vout ratio, if using different ratios then again increasing the inductor value >470uH will help.

Source: http://forum.allaboutcircuits.com/showthread.php?t=7885 

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The emission power of five bands of mobile phone jammer

 The emission power of five bands of mobile phone jammer can be smoothly

adjusted.
This phone is in the end how to design and manufactured it? So today we try to use a technical objective perspective, a brief description of the relationship between the structure of the mobile

phone design department and departments, and finally to show the various tests before the phone to be available by the manufacturer, so that we can further understand the cell phone more cherish

your love machine, perhaps you that it would not easily replace it! handset design process with a relatively simple interpretation of the general mobile phone design companies require a minimum six

departments: ID, the MD, HW, SW, PM, Sourcing, QA. ID (Industry Design) industrial design, including the realization of the phones appearance, texture, feel, color combinations, the main interface

and color design. mobile phone jammer will just shield the cell phone signals and the Wi-Fi signal.
Such as the Motorola "Ming" clamshell translucent, Nokia 7610, the arc-shaped appearance, Sony Ericsson W550 sun orange. These all belong to the special feel and experience of the users mobile

phone industrial design areas, a phone can become the best-selling products, the phones industrial design is of particular importance. The location choice of mobile phone shell, shell, the phones

camera lens fixed way, how to connect the battery, the phones thickness and extent. The slider phone, how to get the phone to slip up, how to achieve the auto-up shells, the SIM card how to insert

and pull out the arrangements, the scope of these cell phones and structural design. Tedious parts of MD staff are very familiar with the materials and processes. The heat resistance of mobile

phone jammer is ultra good.
Motorola V3 to the thickness of 13.9mm set off a craze of mobile phone market, V3 cell phone with ultra-thin as the selling point, because its phone casing material selection is critical, so V3

shell crafted by the advanced technology of aviation grade aluminum material. Can be said that the special choice of shell material achievements of the success of the V3. Addition, individual user

reaction when some of the ultra-thin slider phone, answer the phone can always feel the phone before the shell from side to side, this is the phone structural design problems, due to the shell of

the phone is too thin. speaker vibration when a call is easy to let the phones body to produce resonance.

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Loudspeaker Protector Monitors Current

This circuit uses a 0.1O 1W resistor connected in series with the output of a power amplifier. When the amplifier is delivering 100W into an 8O load, the resistor will be dissipating 1.25W. The resulting temperature rise is sensed by a thermistor which is thermally bonded to the resistor. The thermistor is connected in series with a resistor string which is monitored by the non-inverting (+) inputs of four comparators in an LM339 quad comparator. All of the comparator inverting inputs are connected to an adjustable threshold voltage provided by trimpot VR1. As the thermistor heats up, its resistance increases, raising the voltage along the resistor ladder.

Loudspeaker Protector Circuit diagram:

When the voltage on the non-inverting input of each comparator exceeds the voltage at its inverting input, the output switches high and illuminates the relevant LED. NOR gate latches are connected to the outputs of the third and fourth comparators. When the third comparator switches high, the first latch is set, turning on Q1 and relay 1. This switches in an attenuation network (resistors RA & RB) to reduce the power level. However, if the power level is still excessive, comparator 4 will switch, setting its latch and turning on Q2 and relay 2.

This disconnects the loudspeaker load. The thermistor then needs to cool down before normal operation will be restored. The values of R1-R4 depend on the thermistor used. For example, if a thermistor with a resistance of 1.5kO at 25°C is used, then R1 could be around 1.5kO and R2, R3 and R4 would each be 100O (depending the temperature coefficient of the thermistor). The setup procedure involves connecting a sinewave oscillator to the input of the power amplifier and using a dummy load for the output. Set the power level desired and adjust trimpot VR1 to light LED1. Then increase the power to check that the other LEDs light at satisfactory levels.

Source:  http://www.ecircuitslab.com/2011/06/loudspeaker-protector-monitors-current.html

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