Low Voltage Supply and Regulation Henryk Palka, IFJ Krakow, DEPFET-Belle II meeting MPI, March 08, 2010 Low Voltage Supply and Regulation

Low voltages for DEPFET Henryk Palka, IFJ Krakow, DEPFET-Belle II meeting MPI, March 08, 2010 Low voltages for DEPFET 18 voltage lines x 40 half-ladders = 720 PS output channels 1) Can be prohibitive in price (100’s k€) 2) PSs 20-30m away from the ladders  difficult (imposible?) to regulate voltage drop at the PS in 2.3A lines R= 5mΩ/m * 30m [10 mm2 cable] + 1.72*10-8 Ωm *0.5 m/(17*10-6 m *3.48*10-3 m) = 150 mΩ + 145 mΩ = 295 mΩ ΔV = 2.3A * 0.295Ω = 0.68 V (at V0=1.8V) → voltage regulators needed, near to the ladder then the number of PS output channels/half-ladder can be reduced, naively to 4 (+2.5V, +3.0V,+20V, -20V), in practice to several channels

Below Vmin of existing radhard regulators. Use voltage dividers? Henryk Palka, IFJ Krakow, DEPFET-Belle II meeting MPI, March 08, 2010 VDDA 1.8 2.3 VDDD 1.8 0.8 VDDIO 1.8 0.1 VJTAG 1.8 0.004 VDDIO 1.8 0.904 VDDC 1.2 0.5 PS 3V, 5A REFIN 1.1 0.1 AMPLOW 0.35 1.5 PS 2.5V, 2A Below Vmin of existing radhard regulators. Use voltage dividers? Vclear_on 17 0.03 Vbulk 17 0 Vgate_off 13 0.03 Vclear_off 8 0.03 Vsource 7 0.1 Vccg 7 0 Vgate_on 4 0.03 Vguard ? PS 20V, 0.5A PS -20V, 0.5A Static voltages, need any regulation? (fixed voltages with no sensing?)

Henryk Palka, IFJ Krakow, DEPFET-Belle II meeting MPI, March 08, 2010 DEPFET Voltages

Where to place the regulators: Henryk Palka, IFJ Krakow, DEPFET-Belle II meeting MPI, March 08, 2010 Where to place the regulators: x 40 Power unit (rack) Dock DHH Half-module ~0.5m ~20m ~2m regulators? regulators? space? Regulators placed at Docks: -add less than 7% to overall resistance do not heat up the region which is already critical for cooling Less radiation hazard (the level O(108 n/cm2/yr) ?)

Use radiation tested regulators? Henryk Palka, IFJ Krakow, DEPFET-Belle II meeting MPI, March 08, 2010 Use radiation tested regulators? Plain regulators are chip and available in all varieties Radiation tested are few: RHL4913A (STM) used in ATLAS, regulates down to 1.22 V, Imax=2A (3A in SMD package) LM117 (NS) used in CMS, min Vout=1.23V, Imax=0.8A RH1086 (Linear Tech.), used in Alice, CMS (?) min Vout=1.23V, Imax=1.5A - MIC5209 (Micrel) min Vout=1.24V, Imax=0.5A 5950RH (M.S.Kennedy) min Vout=2.5V, Imax=5A AN1081 (Int. Rectifier) min Vout=1.26V, Imax=3A None goes below 1.2 V Availability is another concern

RHFL4913A: VIN = 3 - 12 V VOUT = 1.2 – 9 V Vd = ~1V Henryk Palka, IFJ Krakow, DEPFET-Belle II meeting MPI, March 08, 2010 RHFL4913A: ~5% of IL goes into sense wire Rsense important! ATLAS: remote sensing, protection: over- voltage, current, temperature Monitoring CAN Bus VIN = 3 - 12 V VOUT = 1.2 – 9 V Vd = ~1V Pmax = 15 W (~ VIN/VOUT) Occupies ~ 3.0 cm2 (+external) Some experience at the Institute in using this chip for ATLAS TRT regulator board (Bartek Kisielewski) Test board to study how it works for Belle II conditions More coll. needed to form a critical mass

- voltages to be regulated by dedicated circuity Henryk Palka, IFJ Krakow, DEPFET-Belle II meeting MPI, March 08, 2010 Conclusions We ought to define - voltages to be regulated by dedicated circuity (mix of PS regulated and custom regulated? Nightmare?) - needed accuracy of the regulation and load currents ranges - which of the supply lines are current source/current sink - fix resistivity of the lines - which protocol for controls (GPIB, CANBus,…)