Today I would like to show You one of my oldest design of series voltage regulator. V1.2 is exactly V1.0 with greater reference voltage and lot of space for output capacitor. It is also produced on gold plated PCB’s.
V1.2 is constant current sourced biased regulator. It is closed loop device with error amplifier based on single transistor. Voltage reference is done by 2 LEDs. Only transistor/diode design allows to make positive and negative versions of this regulator.
This design is mostly used by my to supply analog circuits with voltages +/-12V and +/-15V. It is also good choice as voltage pre-regulator before accurate and fast V3.1 and V2.1 designs. I use it as output regulator of clock power supply:
Today I would like to show You one of my bipolar power supplies. It is based on same topology like in V3.X series but with cascade bias constant current source and with CCS in Vref.
Board are very compact. Only few largest component are located at top side of PCB – rest are in SMD on bottom side.
Shape of the board, dimensions and mounting holes positions are the same like in rest of my bipolar power supplies so can be swapped for choosing the best for us.
Dimensions of PCB: 60 x 82mm
Integrated constant current sources and voltage reference circuit consist 12 LED’s so board emits light also. Output voltage is set by feedback voltage divider mounted on board – should be set during assembling.
To use this power supply You must provide only 2 x AC voltage to connectors one one edge of PCB. Here You can find example of use with my transformer board:
Next amplifier for HeadFun is based on TPA6120 TI current feedback, high current, operational amplifier + Linear LT1028 for input buffer/voltage amplification. TPA6120 needs input buffer on non-inverting input due to ~6uA of current sourcing from this pin.
Next headphone amplifier module designed to use witch HeadFun mainboard is based on LME49600/610 TI buffer witch LT1028 voltage amplifier and LT1055 DC servo.
Electrolytic and DC servo capacitors are mounted at bottom side of PCB. I really like this combination of opamps. LT1028 and AD797 are my favourite opamps for voltage amplification. LT1055 has very good performance in DC servos cause of low input current and low current noise. This combined with big values of resistors at input gives good noise performance.
Feedback loop is voltage type. Voltage amplification is set to 10x.
Today I want show You my modular Headphone Amplifier design. I want to test best headphone amplifier circuit in my DAC, so I decided to make it modular. When I designed 4 different modules but whole DAC is still not completed, I decide to make motherboard that creates complete and safe in use headphone amplifier. Additional RCA output allows use it as preamplifier.
Whole amplifier has modular design. Motherboard contains:
10/16VA Power supply
4 piece of my voltage regulator (dedicated is V3.0max)
volume control eg. ladder like in photo
output protection circuit with AC voltage interruption detection and delayed ON
set of input/output connectors
amplifier modules socket
So You can freely replace regulators and amplifier modules.
Here is complete amplifier with V3.0max regulators and HDP01 current feedback amplifier:
Board at night:
Please choose the right module from menu for detailed description.
Till today I have done 5 different amplifier modules:
1. HDP01 discrete current feedback amplifier
2. Bipolar, discrete, current feedback amplifier with MOSFET output
Till today (24 April 2015) I have designed 14 versions of voltage regulators of whichas many as 9 are newly and my own topologies. I know You could have a problem to choose a right one for Your application, so I would like to explain You differences between all versions.
In general there are 3 groups.
discrete series regulators
discrete shunt regulators
integrated regulators (series)
In explanation:
V1.0 – simple series regulator with NPN output, single transistor error amplifier, LED voltage reference and CSS bias circuit.
V1.1 – simple series regulator with Szikai output, single transistor error amplifier, LED voltage reference and CSS bias circuit.
V1.2 – V1.0 with some improvement for high output voltage, gold plated PCBs.
V2.0 – series regulator with opamp error amplifier, Szikai output, LED voltage reference and CCS bias circuit.
V2.1 – series regulator with opamp error amplifier, NPN output, LED voltage reference and CCS bias circuit, gold plated PCBs.
V3.0 – series regulator with transistor differential amplifier, NPN output, LED voltage reference, CCS bias circuit.
V3.1 – V3.0 with some improvements for better soldering, precision voltage reference, precision output voltage set, gold plated PCBs.
V3.0max – V3.0 with improvements for high output voltage, gold plated PCBs.
V4.0 – shunt regulator based on TL431 with Sziklai CCS, gold plated PCBs.
V5.0 – series regulator with opamp error amplifier in shunt configuraton, gold plated PCBs.
V6.1 – series regulator based on Texas Instruments TPS7A4700/3301, gold plated PCBs.
V8.0 – shunt regulator with transistor differential amplifier, Sziklai CCS, precision/LED voltage reference, gold plated PCBs.
All deigns (excluding V3.0max) are made on 30mm x 15mm PCBs like this:
Pinout always are:
IN
IN
GND
OUT
OUT
so they can replace integrated regulators like 78XX or discrete like TPA Trident Shunt.
You can use only 3 center pins for replacement of 78XX, or all 5 pins when board is designed to use my discrete regulators.
For better heat dissipation external heatsink can be used. I use Fisher heatsinks mounted by 3M heat-conductive tape:
This tape can be also used to stick the regulator to any metal elements of Your device. Here You can find V1.0 regulators mounted on Revox B226 CD to provide better opamp supply:
For detailed information about specific version please choose right one from menu. Not all version are carefully described on my page.
In this post I would like to show you my newest project – a precise clock signal generator for Hi-End audio equipment like: CD players, audio DACs, USB converters etc. An output signal is a real square wave, with ~50% duty cycle and output impedance is real 50R!
Oscillator circuit based on Colpitts topology delivers clean sinusoidal signal with accurate frequency given by 5ppm crystal from OMIG. Oscillator circuit is closed in EMI shield to provide environment free from disturbances and stable ambient temperature. Additionally, internal shunt regulator heats the crystal to optimal temperature for stable operation. The interioris filled withheat resistive material to increase temperature stability.
Output signal forming circuit is based on ultra high speed comparator. Additional circuit automatically sets duty cycle to 50% at the output.
Falling slope:
Falling slope time is very close to rising – from 10% to 90% ~500ps.
Clean power to oscillator and output circuit provides 2pcs of V8.0 shunt regulators which are located very close to load. One of this regulators is also used to heat crystal inside temperature chamber.
Power for whole circuit is also filtered by common mode input filter. It also block EMC conducted emissions to passed from clock to cables and power supply.
Results:
Output signal wideband spectrum in linear scale:
Output signal narrowband spectrum in logarithmic scale:
Output signal Jitter analysis:
Dimensions and connector position:
Test in climatic chamber:
Power requirements: 8-10V, 120mA.
Environmental temperature: -40 to +85 Celsius degree (checked in climatic chamber)
Initial accuracy: <0,1ppm
Accuracy over temperature range -40 to +85: <50ppm (checked in climatic chamber)
MuzgDIY 