lasercurrentsourcev2

     

lasercurrentsourcev2 Release status: experimental [box doku]
Description	3channel currentsource
Author(s)	siro
Last Version	-

english version of Laserprojector/lasercurrentsourcev2.
project Laserprojector

Idea

Tripple channel high speed digital adjustable current source for laser video applications.

requirements

• adjustable offset per channel
• 30bit - true 1G colors (3 different laser diodes)
• Hardware Gammacorrection (Rev1.1?)
• VGA-input/HDMI input with FPGA (Sauron) (Rev1.1?)
• more than 10MSPs
• adjustable diode voltage to reduce power consumption
• adjustable gain per channel 1x - 50x
• adjustable DAC gain

• compatible to
  • LPC2103 (ARM7)
  • STM32F103 (Cortex M3)
  • Spartan3 Starter Kit

Laser-diodes

• 20mW Red : 90mA Diode Current
• 50mW Greeb: 350mA Diode Current
• 450mW Blue: 600mA Diode Current

Rev 1.0

• 

  SMD version 1.0 oben

Specification

• 24 V max AC/DC
• up to 500 - 600 mA per channel TODO: messure
• up to 1.9W power draw per channel
• up to 330Mhz TODO: messure
• adjustable offset per channel
• 30bit - true 1G colors (3 different laser diodes)
• more than 10MSPs
• adjustable diode voltage to reduce power consumption
• adjustable gain per channel 1x - 50x
• adjustable DAC gain

Messured

• 150mA Amplitude
  • Slew Rate 6.5A/µs
  • output delay (rising Clock, dI/dt = 0) ~48ns
  • fall time 18.5 ns
  • max freq. 50Mhz

Dimension

• 107mm x 80mm
• Double Layer, 0.3>mm drill, 0.15mm width

parts

• Induktor:
  • L-PISM 68µ
  • L-PIS2816 680µ
  • L-PIS2816 22µ

• DC/DC converter:
  • LM2574HVM-5.0 (SIMPLE SWITCHER 5V 0.5A Step-Down Voltage Regulator)
  • LM2596TV (3.0A, 150Khz, Step-Down Switching Regulator)

• ELKO:
  • Elko SMD-Bauform, 105°C, low ESR 10µ
  • Elko SMD-Bauform, 105°C, low ESR 47µ
  • Elko SMD-Bauform, 105°C, low ESR 220µ

• Transistor:
  • NESG270034 (Stromspiegel)
  • MMDT3906VCDICT-ND (Bias)

• ADC:
  • ADV7123KSTZ50-ND (Triple Channel 10bit Parallel DAC 330Msps)

• Trimmer:
  • TRIMMER 100 OHM 0.125W SMD
  • TRIMMER 100K OHM 0.5W TH

• rectifier:
  • DIODE SCHOTTKY 1A 60V MBS-1

Supplier

Digikey:

9	NESG270034-T1-AZCT-ND
1	LM2574HVM-5.0-ND
1	LM2596T-ADJ-ND
1	PCE4976CT-ND 10µ
3	PCE4951CT-ND 47µ
2	PCE5009CT-ND 220µ 
1      HS287-ND Heat Sink
1      MB16S-TPMSCT-ND Rectifier
5      277-1721-ND Connectors
1      B260-FDICT-ND DIODE 
1      MBRS360BT3GOSCT-ND DIODE
3      568-4117-1-ND Diode
3      ST32ETB101CT-ND Trimmer 100
5      MMDT3906-FDICT-ND PNP Dual
5      MMDT3904-FDICT-ND NPN Dual
3      490-2895-ND TRIMMER 100K
6      P160DACT-ND 160ohm
1      RR12P681DCT-ND 681ohm
1      RHRA-1.0-ND
1      RHRA-5.0-ND
1      805F2R0E-ND
3      WSCB-2.0CT-ND

Reichelt:

1      L-PISM 68µ
1      L-PIS2816 680µ
1      L-PIS2816 22µ 
10     X7R-G0805 100N
10     X7R-G0603 100N
1      WSL 40W
5      BL 1X20G7 2,54

note: some parts may be missing

Schematics

• 
• 

Powerdraw

P(T1) = Uce * Ic = 1.8W max
Uce = Ub - (Uf(Ic) + Ic * 2)

Example:

Ub = 5V
Uf(100mA) = 2.5V
Ic = 100mA
P(T1) = Ic * (Ub - Uf(Ic) - Ic * 2)
      = Ic * Ub - Ic * Uf(Ic) - Ic^2 *2
      = 0.1A * 5V - 0.1A * 2.5V - 0.1A^2 * 2
      = 0.5W - 0.25W - 0.02W
      = 0.23W

Ub = 7V
Uf(100mA) = 2.5V
Ic = 100mA
P(T1) = Ic * (Ub - Uf(Ic) - Ic * 2)
      = Ic * Ub - Ic * Uf(Ic) - Ic^2 *2
      = 0.1A * 7V - 0.1A * 2.5V - 0.1A^2 * 2
      = 0.7W - 0.25W - 0.02W
      = 0.48W

Ub = 7V
Uf(500mA) = 2.8V
Ic = 500mA
P(T1) = Ic * (Ub - Uf(Ic) - Ic * 2)
      = Ic * Ub - Ic * Uf(Ic) - Ic^2 *2
      = 0.5A * 7V - 0.5A * 2.5V - 0.5A^2 * 2
      = 3.5W - 1.25W - 0.5W
      = 1.75W

Ub = 8V
Uf(500mA) = 2.1V
Ic = 500mA
P(T1) = Ic * (Ub - Uf(Ic) - Ic * 2)
      = Ic * Ub - Ic * Uf(Ic) - Ic^2 *2
      = 0.5A * 8V - 0.5A * 2.1V - 0.5A^2 * 2
      = 4W - 1.05W - 0.5W
      = 2.45W 
 2.45W > 1.8W : use resistor in series with Laserdiode to increase Uf(Ic) !!! 

Errors

• do not use NESG270034, base and collector are swap !
• pin-header for MP2103-Stick have to wrong distance
• one elko 10µF matches with the headsink
• headsink is to big
• great current after power on, init microcontroller first and set low level as soon as possible
• A3 via ist partly connected to ground !

Rev 1.1

Specification

TODO

Dimension

• 85mm x 80mm
• Double Layer, 0.3>mm drill, 0.15mm width

Parts

• Induktor:

TODO

• Spannungsregler: http://www.ti.com/lit/ds/symlink/tps54332.pdf

TODO

• ELKO:

TODO

• Transistor:

TODO

• ADC:
  • ADV7123KSTZ50-ND (Triple Channel 10bit Parallel DAC 330Msps)

TODO

• Stromversorgung:
  • HEBW 25 :: Hohlstecker-Einbaubuchse, gewinkelt, Lötfahnen

TODO

Supplier

Digikey:

TODO

Reichelt:

TODO

Schematics

TODO