monsonfields ipdr – lnps spp/fields low noise power supply preliminary design review steve monson...
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Monson 1FIELDS iPDR – LNPS
SPP/FIELDSLow Noise Power Supply
Preliminary Design Review
Steve Monson
University of Minnesota
Monson 2FIELDS iPDR – LNPS
3D View of Main Electronics Package
Monson 3FIELDS iPDR – LNPS
SPP FIELDS Instrument Block Diagram
Monson 4FIELDS 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
Monson 5FIELDS iPDR – LNPS
Comparison
• STEREO/WAVES SPP/FIELDS
15 watts primary LNPS1 11w (25 C) 15w (55 C)
LNPS2 7w (25 C) 9w (55 C)
100 kHz 150 kHz
LTC1149 switching regulator MSKennedy 5055RH(plastic) (LT3845A rad
hard dice)
HS1825ARH pulse width modulator same
25 C 55 C
Monson 6FIELDS iPDR – LNPS
LNPS Block Diagram
Monson 7FIELDS iPDR – LNPS
LNPS1 Customers
DCB RFS DFB AEB SCM MAG(mA) (mA) (mA) (mA) (mA) (mA)
• 1.8V 500 728• 3.3V 450 428 1• 4V 170• 5V 150• +6V 41 24 12• -6V 41 19 12• +12V 4 11 12 52• -12V 4 11 12 28• +100V .5• -100V .5
Total 14.5 watts primary at 55 degrees C
Monson 8FIELDS iPDR – LNPS
LNPS2 Customers
TDS AEB2 MAG(mA) (mA) (mA)
• 1.8V 500• 3.3V 450 1• 5V 111• +6V 60 12• -6V 60 12• +12V 7 52• -12V 7 28• +100V .3• -100V .3
Total 8.3 watts primary at 55 degrees C
Monson 9FIELDS iPDR – LNPS
Peer Review Action Items
Monson 10FIELDS 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.
Monson 11FIELDS iPDR – LNPS
• 95% efficient at 11 watts
• 1 watt change causes only 1 mV change in output
12V Pre-Regulator
Monson 12FIELDS iPDR – LNPS
Turn On Delay
• Flight instrument will haveAEB +/-100V delayed from +5Vby 100ms
• Top: 12V Pre-Regulator 10V/div
• Middle: 3.3V 2V/div– Comes from first PWM
• Bottom: 4V 2V/div– Comes from 2nd PWM
• Time: 25 ms/div
Monson 13FIELDS iPDR – LNPS
Low Voltage Turn 0n
• 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
Monson 14FIELDS iPDR – LNPS
Inrush current
• 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 a
mp /
div
STEREO/WAVES
SPP Requirements
Monson 15FIELDS 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