MonsonFIELDS iPDR – LNPS SPP/FIELDS Low Noise Power Supply Preliminary Design Review Steve Monson University of Minnesota 1

MonsonFIELDS iPDR – LNPS 3D View of Main Electronics Package 2

MonsonFIELDS iPDR – LNPS SPP FIELDS Instrument Block Diagram 3

MonsonFIELDS iPDR – LNPS LNPS Requirements Operate from 22 to 35 VDC Operate over the range of -25 C to +65 C base plate temperature Must sync at 150 kHz but operate nominally without sync Provide ten DC voltage supplies –1.8V, 3.3V, 4V, 5V, +/- 6V, +/- 12V, +/- 100V –+/-100V supply to be delayed by 100ms from 5V supply (AEB) Total secondary power to be approx. 9w for LNPS1 and 5w for LNPS2 Monitor Housekeeping (10 voltages, LNPS temp and one SCM temp) Provide sense circuit and control for SCM heater Provide pass through of some additional lines –Primary heater power for MAG and Preamps –Temperature feedback for MAG, SCM and Preamps 4

MonsonFIELDS iPDR – LNPS Comparison STEREO/WAVESSPP/FIELDS 15 watts primaryLNPS1 11w (25 C) 15w (55 C) LNPS2 7w (25 C) 9w (55 C) 100 kHz150 kHz LTC1149 switching regulatorMSKennedy 5055RH (plastic)(LT3845A rad hard dice) HS1825ARH pulse width modulator same 25 C55 C 5

MonsonFIELDS iPDR – LNPS LNPS Block Diagram 6

MonsonFIELDS iPDR – LNPS LNPS1 Customers DCBRFSDFBAEBSCMMAG (mA)(mA)(mA)(mA)(mA)(mA) 1.8V V V170 5V150 +6V V V V V V.5 Total 14.5 watts primary at 55 degrees C 7

MonsonFIELDS iPDR – LNPS LNPS2 Customers TDSAEB2MAG (mA)(mA)(mA) 1.8V V V111 +6V V V V V V.3 Total 8.3 watts primary at 55 degrees C 8

MonsonFIELDS iPDR – LNPS Peer Review Action Items 9

MonsonFIELDS iPDR – LNPS 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 makes 150kHz for Pre-Regulator and 300kHz for first PWM Second and third PWMs are slaved from the first Pre-regulator and 3 PWMs all operate in sync from 16V to 40V input. In the event of sync failure, all 4 free run at ~135kHz whether sync stops up, stops down, or is removed completely. 10

MonsonFIELDS iPDR – LNPS 95% efficient at 11 watts 1 watt change causes only 1 mV change in output 11 12V Pre-Regulator

MonsonFIELDS iPDR – LNPS Turn On Delay Flight instrument will have AEB +/-100V delayed from +5V by 100ms Top: 12V Pre-Regulator 10V/div Middle: 3.3V 2V/div –Comes from first PWM Bottom: 4V 2V/div –Comes from 2 nd PWM Time: 25 ms/div 12

MonsonFIELDS iPDR – LNPS Low Voltage Turn 0n 13 Tested a breadboard with the Pre-regulator and two PWMs 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

MonsonFIELDS iPDR – LNPS Inrush current 14 SPP has same specs as STEREO SPP/FIELDS will be very similar to STEREO/WAVES which was well within spec 100ms delay of one PWM will lower first spike and make a second smaller peak at 100ms 1 ms / div 1 amp / div STEREO/WAVES SPP Requirements

MonsonFIELDS iPDR – LNPS Conclusion All components have been bread-boarded and tested Issues –LNPS operating temperatures are high (55C) –LNPS1 parts layout is crowded –Both issues are being resolved Next –LNPS1 brass board layout is in the works – ETU form and function –LNPS1 BB TV is planned –ETU final designs Preliminary LNPS design meets requirements LNPS is ready to proceed with ETU development 15