MonsonPeer Review – 5 December 2014 SPP/FIELDS LNPS PEER REVIEW Steven Monson University of Minnesota 1

MonsonPeer Review – 5 December D View of Main Electronics Package 2

MonsonPeer Review – 5 December 2014 SPP FIELDS Instrument Block Diagram 3

MonsonPeer Review – 5 December 2014 LNPS Requirements Operate from 22 to 35 VDC Operate over the range of -25 to +60 degrees C base plate temperature –(derating to 75 C worst case board temperature) Must sync at 150 kHz but operate nominally without sync Provide DC voltage supplies –LNPS1 1.8V, 3.3V, 4V, 5V, +/- 6V, +/- 12V, +/- 100V –LNPS2 1.5V, 3.3V, 5V, +/- 6V, +/- 12V, +/- 100V –+/-100V supply to be delayed by 100ms from 5V supply (AEB requirement) Total secondary power about 9.3w for LNPS1 and 5.7w for LNPS2 Monitor and multiplex 10 voltages, LNPS temp and one SCM temp Provide sense circuit and control for SCM heater (LNPS1) Provide pass through of heater power for MAG 4

MonsonPeer Review – 5 December 2014 LNPS1 Customers DCBRFSDFBAEB1SCMMAGo (mA)(mA)(mA)(mA)(mA)(mA) 1.8V250 (500)364 (728) 3.3V300 (450)125 (189) 1 4V V120 +6V V V V V V.5 Total 13 watts primary (16 hot) 5

MonsonPeer Review – 5 December 2014 LNPS2 Customers TDSAEB2MAGi (mA)(mA)(mA) 1.5V250 (500) 3.3V300 (450) 1 5V80 +6V V V V V V.3 Total 8 watts primary (10 hot) 6

MonsonPeer Review – 5 December 2014 Changes from one year ago Added MSKennedy regulators due to large current increases when hot –Changes in voltage losses in transformer, diodes, filter inductor and CMC would have totaled.6V because of large current variations –1.9V linear regulator on 1.8V power to DCB (LNPS1) –1.9V linear regulator on 1.8V power to DFB (LNPS1) –1.5V linear regulator on 1.5V power to TDS (LNPS2) Moved +/-100V supply to its own transformer SCM heater power switch moved from low side to high side Replaced Aeroflex UT16MX channel multiplexer with an Intersil HS for ease of use and reliability issues Eliminated three connectors from each –J06/J86 Preamp 1/3 heater line pass through –J07/J87 Preamp 2/4 heater line pass through –J08/J88 Preamp, SCM and MAG SCTemp lines 7

MonsonPeer Review – 5 December 2014 LNPS1_EM 8

MonsonPeer Review – 5 December 2014 LNPS2_EM 9

MonsonPeer Review – 5 December 2014 LNPS1 Block Diagram 10

MonsonPeer Review – 5 December 2014 LNPS2 Block Diagram 11

MonsonPeer Review – 5 December 2014 SYNC at 150 kHz Pre-Regulator and PWMs free run at 135kHz 600 kHz square wave clock –generated by DCB for LNPS1 –generated by TDS for LNPS2 Binary counter (HC4024) makes 150kHz for Pre-Regulator and 300kHz for first PWM Second and third (LNPS1 only) PWM slaved from the first All operate in sync from 16V to 40V input. In the event of sync failure, all will free run whether sync stops up, stops down, or is removed completely. 12

MonsonPeer Review – 5 December 2014 FET Testing and Selection Transformer drive FET selection was critical At 150kHz drain-source on resistance is not the most important Input capacitance, turn on delay time, rise time, turn off delay time, fall time are all important Tested 8 types of commercial International Rectifier FETs in LNPS breadboard Selected the IR rad-hard part that closest matched the specs of the one that was the most efficient JANSR2N7488T3 in a medium size TO-257AA package is efficient, runs cool and has a heat sink mounting tab. 13

MonsonPeer Review – 5 December 2014 POT Cores Ferroxcube pot cores are used for the transformers, filter inductors, and common mode chokes –Minnesota has used hundreds of these on dozens of projects –We have a standard procedure for their manufacture and testing –They will be wound and assembled by the technician who has made just about all of them Screening –Measure DC resistance of all windings Inductance of all windings Insulation resistance –Check dielectric withstanding voltage –Perform temperature cycles and thermal shock –Repeat all measurements and reject any that changed beyond specified limits 14

MonsonPeer Review – 5 December % efficient in operating region 1 watt change causes only 1 mV change in output (Graph is for LNPS1) 15 12V Pre-Regulator Input watts at 30 Volts

MonsonPeer Review – 5 December 2014 LNPS2 Turn On Delay AEB +/-100V will be delayed from +5V by 100ms Top: 12V Pre-Regulator 10V/div Middle: 5V 2V/div Bottom: 100V 50V/div Time: 25 ms/div 16

MonsonPeer Review – 5 December 2014 Voltage Ripple 100mV peak spikes at 150kHz switching frequency 15mV – 20mV noise in between spikes DC-Low frequency noise will depend on the load variations of the various customers 17

MonsonPeer Review – 5 December 2014 LNPS1 Max and Min Voltage Specifications SupplyMaxMin 1.9V1.90 Regulated1.80 (after filter and CMC losses) 3.3V V V / / / The numbers above are the specs. -The three +/- supplies have little load variation and I will try to set them on the low side; i.e, 5.8, 11.8 and 98. -The 3.3V has the largest load variation and therefore the entire 3.14 – 3.46 may be seen. -Load resistors will keep no load voltages to reasonable values. 18

MonsonPeer Review – 5 December 2014 LNPS1 Temperatures Above Plate 19 Thermo-Vac performed at 60 and 70 C base plate

MonsonPeer Review – 5 December 2014 Low Voltage Turn 0n 20 Turned on instrument in 1/3 volt increments from 0 to 28V No evidence of a high current mode where two FETS were on at the same time

MonsonPeer Review – 5 December 2014 In-rush current 21 These photos are for LNPS2 In-rush current will not be a problem 1 ms / div 0.5 amps / div SPP Requirements 5 amps / div 25 ms / div

MonsonPeer Review – 5 December 2014 Coming up Finish load boxes for LNPS2 Brief LNPS2 Thermo-Vac –Measure warm points with 60 and 70 C base plate Integrate LNPS2 with TDS Deliver LNPS2 to UCB (with TDS) Build second LNPS2 22