Nice project prasimix.
How much did all those PCBs set you back?
Nice project. I can see you put alot of effort into it, is it your schematic or from an already published/tested project ? The reason I ask is that I think there may be a stability/CC performance issue due to the way Q4 is driven. Do you have a spice sim available to post (just the basic main control loop components is all thats needed to show if this is so Q4,Q5,Q6, IC7A-IC7D and associated small stuff) .
Regards
Edit .I should have read the other few posts above I see someone says it's a kit from JYETech.com .Still do you have a sim available ?
/*
Melody
Plays a melody
created 21 Jan 2010
modified 30 Aug 2011
by Tom Igoe
This example code is in the public domain.
http://arduino.cc/en/Tutorial/Tone
*/
#include "pitches.h"
// notes in the melody:
int melody[] = {
NOTE_C4, NOTE_G3,NOTE_G3, NOTE_A3, NOTE_G3,0, NOTE_B3, NOTE_C4};
// note durations: 4 = quarter note, 8 = eighth note, etc.:
int noteDurations[] = {
4, 8, 8, 4,4,4,4,4 };
void setup() {
// iterate over the notes of the melody:
for (int thisNote = 0; thisNote < 8; thisNote++) {
// to calculate the note duration, take one second
// divided by the note type.
//e.g. quarter note = 1000 / 4, eighth note = 1000/8, etc.
int noteDuration = 1000/noteDurations[thisNote];
tone(A1, melody[thisNote],noteDuration); // Arduino pin A1 is PF6 (Pin 37) assigned to BUZZER
// to distinguish the notes, set a minimum time between them.
// the note's duration + 30% seems to work well:
int pauseBetweenNotes = noteDuration * 1.30;
delay(pauseBetweenNotes);
// stop the tone playing:
noTone(A1);
}
}
void loop() {
// no need to repeat the melody.
}
/*************************************************
* Public Constants
*************************************************/
#define NOTE_B0 31
#define NOTE_C1 33
#define NOTE_CS1 35
#define NOTE_D1 37
#define NOTE_DS1 39
#define NOTE_E1 41
#define NOTE_F1 44
#define NOTE_FS1 46
#define NOTE_G1 49
#define NOTE_GS1 52
#define NOTE_A1 55
#define NOTE_AS1 58
#define NOTE_B1 62
#define NOTE_C2 65
#define NOTE_CS2 69
#define NOTE_D2 73
#define NOTE_DS2 78
#define NOTE_E2 82
#define NOTE_F2 87
#define NOTE_FS2 93
#define NOTE_G2 98
#define NOTE_GS2 104
#define NOTE_A2 110
#define NOTE_AS2 117
#define NOTE_B2 123
#define NOTE_C3 131
#define NOTE_CS3 139
#define NOTE_D3 147
#define NOTE_DS3 156
#define NOTE_E3 165
#define NOTE_F3 175
#define NOTE_FS3 185
#define NOTE_G3 196
#define NOTE_GS3 208
#define NOTE_A3 220
#define NOTE_AS3 233
#define NOTE_B3 247
#define NOTE_C4 262
#define NOTE_CS4 277
#define NOTE_D4 294
#define NOTE_DS4 311
#define NOTE_E4 330
#define NOTE_F4 349
#define NOTE_FS4 370
#define NOTE_G4 392
#define NOTE_GS4 415
#define NOTE_A4 440
#define NOTE_AS4 466
#define NOTE_B4 494
#define NOTE_C5 523
#define NOTE_CS5 554
#define NOTE_D5 587
#define NOTE_DS5 622
#define NOTE_E5 659
#define NOTE_F5 698
#define NOTE_FS5 740
#define NOTE_G5 784
#define NOTE_GS5 831
#define NOTE_A5 880
#define NOTE_AS5 932
#define NOTE_B5 988
#define NOTE_C6 1047
#define NOTE_CS6 1109
#define NOTE_D6 1175
#define NOTE_DS6 1245
#define NOTE_E6 1319
#define NOTE_F6 1397
#define NOTE_FS6 1480
#define NOTE_G6 1568
#define NOTE_GS6 1661
#define NOTE_A6 1760
#define NOTE_AS6 1865
#define NOTE_B6 1976
#define NOTE_C7 2093
#define NOTE_CS7 2217
#define NOTE_D7 2349
#define NOTE_DS7 2489
#define NOTE_E7 2637
#define NOTE_F7 2794
#define NOTE_FS7 2960
#define NOTE_G7 3136
#define NOTE_GS7 3322
#define NOTE_A7 3520
#define NOTE_AS7 3729
#define NOTE_B7 3951
#define NOTE_C8 4186
#define NOTE_CS8 4435
#define NOTE_D8 4699
#define NOTE_DS8 4978
#include "U8glib.h" // Universal 8bit Graphics Library, http://code.google.com/p/u8glib/
// Define LCD type
// devices with all constructor calls is here: http://code.google.com/p/u8glib/wiki/device
U8GLIB_ST7920_128X64_1X u8g(A0); // Arduino Pin A0 is PF7 (pin 36) assigned to LCD_SELECT
void draw(void) {
// graphic commands to redraw the complete screen should be placed here
//u8g.setFont(u8g_font_unifont);
u8g.setFont(u8g_font_tpss);
//u8g.setFont(u8g_font_osb21);
//u8g.setFont(u8g_font_04b_03b);
u8g.drawStr( 0, 10, "Welcome screen");
u8g.drawStr( 0, 22, "PSU dual 0-50V/0-3A");
u8g.setFont(u8g_font_04b_03b);
u8g.drawStr( 0, 30, "- SMPS pre-regulator");
u8g.drawStr( 0, 36, "- Linear post-regulator");
u8g.drawStr( 0, 42, "- CC/CV, OCP");
u8g.drawStr( 0, 48, "- 16-bit DAC, 15-bit ADC");
u8g.drawStr( 0, 54, "- Isolated USB and Ethernet");
u8g.drawStr( 0, 60, "- Arduino sketches");
}
void setup(void) {
// Set LCD brightness
pinMode(11, OUTPUT); // Arduino Pin 11 is PB7 (pin 12) assigned to LCD_BRIGHTNESS
analogWrite(11, 200); // (value from 0 to 255, 0=dark)
if ( u8g.getMode() == U8G_MODE_R3G3B2 ) {
u8g.setColorIndex(255); // white
}
else if ( u8g.getMode() == U8G_MODE_GRAY2BIT ) {
u8g.setColorIndex(3); // max intensity
}
else if ( u8g.getMode() == U8G_MODE_BW ) {
u8g.setColorIndex(1); // pixel on
}
else if ( u8g.getMode() == U8G_MODE_HICOLOR ) {
u8g.setHiColorByRGB(255,255,255);
}
u8g.firstPage();
do {
draw();
} while( u8g.nextPage() );
}
void loop(void) {
// Nothing to do
}
I tried to get some idea about power dissipation and does current heatsink will be enough for extreme case (50V/3A on output). Measuring Vin and Iin as AC (rms) and Vout and Iout as DC I got the following data:
The highest current is to the left, the lowest to the right. So the efficiency goes down as load decreases ; not surprising but typical.
My idea is to leave TO220 device soldered on the PCB, drill i.e 4mm "thru-hole" on back panel and mounting them with M3 screw to heatsink