Power Supply Sink
The Power Supply Sink is controlled from the PC via a programmable bus interface to set the desired voltage, current or power.
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Interface & Requirements
- SPI Input Interface
- digital with \(U \in [0V, 5V]\) relative to isolated ground
GNDI
isolation voltage max \(V_{iso} = 500V\)!CS_ISO
, input, chip select, low activeSCLK_ISO
, input, serial clock CPHA=0, CPOL=0=SCKL
SDI_ISO
, input, serial data inSDO_ISO
, output, serial data out
- digital with \(U \in [0V, 5V]\) relative to isolated ground
- Voltage output
- \(U_{out} \in [0V, +5V]\)
- \(I_{out} \in [-20A, +20A]\)
- Short circuit I limit \(max(|I_{out}|) \leq |I_{max}| \leq |1.25 max(I_{out})|\)
- Supply Voltages
- \(+10V\) @ \(260W\) (\(26A\))
- \(-5V\) @ \(180W\) (\(26A\))
Supply Voltages
In order to achieve galvanic isolation the provided supply voltages must
provide galvanic isolation. The pss
output voltage is not isolated
internally.
Circuit Selection and Design
SPI Configuration
The spi interface gives the possibility to
- Write configuration from the
pc
to thepss
- Channel Map available at
./conf/channel_map.md
- Datasheet for DAC and SPI Commands
../../hw/pss/datasheet/AD5672RBRUZ.pdf
- Channel Map available at
- Read output voltage from the
pss
to thepc
- Datasheet for ADC and SPI Commands
../../hw/pss/datasheet/ADS8665IPWR.pdf
- Datasheet for ADC and SPI Commands
- Read output current from the
pss
to thepc
- Datasheet for ADC and SPI Commands
../../hw/pss/datasheet/ADS8665IPWR.pdf
- Datasheet for ADC and SPI Commands
Circuit
The overview of the interconnections is given in the block diagram below. The
pc
can program a configuration through the isolated spi digital interface
.
The configuration is converted to the analog domain by the DAC
and fed
through the multiplexer
to the controller
. The controller
controls the
power electronics
to achieve the desired reference quantity at the output,
which is measured by the output measurement
. Depending on the configuration
the output is connected to or disconnected from the load by the relay
sub
circuit. The measurements of the output measurement
can also be read via
the digital-interface
.
The configuration and output measurements are used by the limit-logic
to
determine the control mode. (e.g. voltage control, upper current limit control,
...) The control mode is used to set the multiplexe
to pass the correct
voltage and current of the configuration to the controller
and provide the
appropriate measurement for the mode.
The power is provided by external isolated DC power supplies for the -5V and +10V rail. The +5V rail used for the measurements and analog configuration is generated internally.
Block Diagram
---
title: PSS Design
---
flowchart TB
pc[PC]
ext_power[10 V DC, -5 V DC]
bat[Battery]
subgraph pss[PSS]
direction TB
power[Power: 10V, 5V, -5V]
dig_interface[Digital Inteface Isolated]
conf[DAC Configuration]
direction LR
mux_ref[Multiplexer Reference]
control[PID-Controller]
subgraph pe[Power Electronic]
bias[Bias Stage]
outstage[Linear Power Amplifier]
end
meas[Output Measurement]
mux_meas[Multiplexer Measurement]
relay[Relay]
subgraph limit[Limit-Logic]
comp[Compare-Logic]
mode-tran[Mode Transition]
end
adc[ADC Output Readback]
end
ext_power --> power
pc <--> dig_interface --> conf
meas --> adc --> dig_interface
conf --> mux_ref --> control --> bias --> outstage --> meas --> relay --> bat
meas --> mux_meas --> control
conf --> comp --> mode-tran
limit --> mux_meas
limit --> mux_ref
conf --> relay
Component Selection
Connector Terminal Blocks
Search on Mouser for terminal blocks TDPT 2,5/ 2-SP-5,08
- Fixed Terminal Block
- PCB mounting
- Nominal current \(I \geq 30A\)
- Wire gauge \(1.5mm^2 \leq A \leq 4mm^2\)
- Push in type
- Pitch \(5mm \leq d \leq 9mm\)
- Sort by price
- Prefer family of parts with different multiplicity of connectors available
Simulation
Simulation is available in ./pss.asc
.
Hardware tests in Laboratory
Layout and Assembly Considerations
PCB Layout
Info
Detailed Layout Information available under ./layout.md
.
- Pull up/down for inputs, when stage is isolated, to run other tests.
- Add disconnectors at outputs of sub circuits to obtain isolation for testing
- Place bulky components on single side of board to allow for reflow soldering on both sides of pcb without use of adhesive glue
Assembly
- Pass tests for
power
- Connect power for
digital-interface
and pass tests - Connect power for
conf
,adc
,adc1
- Pass tests for
conf
- Pass tests for
adc
,adc1
- Connect power for
relay
and pass tests - Connect power for
measurement
and pass tests - Connect power for
mux
and pass tests - Connect power for
limit-logic
and pass tests - Connect power for
control-var
and pass tests - Connect power for
power-electronics
and pass tests - Connect Solderbridges
- JP107 - JP110
- JP117 - JP126
- JP101 - JP106
- JP111 - JP112
- JP113
- JP128 - JP129
- Pass tests for
pss
Open Circuit Test
Test ID: v1.0.0/pss/open-circuit/<suffix>
Available suffix:
voltage-control0
,voltage-control3
,voltage-control5
-
lower-voltage-limit-control
,upper-voltage-limit-control
-
Connections
- Output disconnected (\(R \rightarrow \inf\))
- SPI interface connected to
pc
- Power on supply voltage
- Program Configuration with conf_output set
- For suffix
voltage-control0
refselect=U, \(U=0V\), \(I=1A\), \(LVL=1V\), \(UVL=4V\), \(LCL=-10A\), \(UCL=10A\) - For suffix
voltage-control3
refselect=U, \(U=3V\), \(I=1A\), \(LVL=1V\), \(UVL=4V\), \(LCL=-10A\), \(UCL=10A\) - For suffix
voltage-control5
refselect=U, \(U=5V\), \(I=1A\), \(LVL=1V\), \(UVL=4V\), \(LCL=-10A\), \(UCL=10A\) - For suffix
upper-voltage-limit-control
refselect=I, \(U=3V\), \(I=1A\), \(LVL=1V\), \(UVL=4V\), \(LCL=-10A\), \(UCL=10A\) - For suffix
lower-voltage-limit-control
refselect=I, \(U=3V\), \(I=-1A\), \(LVL=1V\), \(UVL=4V\), \(LCL=-10A\), \(UCL=10A\)
- For suffix
- Measure Voltages
- Output Voltage with multimeter \(U_{out,multi}\)
- Output Voltage with internal adc via spi \(U_{out,spi}\)
- Power off supply voltage
- Test passed if
- For suffix
voltage-control0
\(U_{out,multi} \in U_{out,adc} \pm 100mV\) \(U_{out,multi} \in 0V \pm 100mV\) - For suffix
voltage-control3
\(U_{out,multi} \in U_{out,adc} \pm 100mV\) \(U_{out,multi} \in 3V \pm 100mV\) - For suffix
voltage-control5
\(U_{out,multi} \in U_{out,adc} \pm 100mV\) \(U_{out,multi} \in 5V \pm 100mV\) - For suffix
upper-voltage-limit-control
\(U_{out,multi} \in U_{out,adc} \pm 100mV\) \(U_{out,multi} \in 4V \pm 100mV\) - For suffix
lower-voltage-limit-control
\(U_{out,multi} \in U_{out,adc} \pm 100mV\) \(U_{out,multi} \in 1V \pm 100mV\)
- For suffix
Short Circuit Test
Test ID: v1.0.0/pss/short-circuit/<suffix>
Available suffix:
current-control0
,current-control-20
,current-control+20
-
lower-current-limit-control
,upper-current-limit-control
-
Connections
- Output short circuited to ground (\(R \rightarrow 0 \Omega\))
- SPI interface connected to
pc
- Power on supply voltage
- Program Configuration with conf_output set
- For suffix
current-control0
refselect=I, \(U=2V\), \(I=0A\), \(LVL=0V\), \(UVL=4V\), \(LCL=-10A\), \(UCL=10A\) - For suffix
current-control-20
refselect=I, \(U=2V\), \(I=-20A\), \(LVL=0V\), \(UVL=4V\), \(LCL=-10A\), \(UCL=10A\) - For suffix
current-control+20
refselect=I, \(U=2V\), \(I=+20A\), \(LVL=0V\), \(UVL=4V\), \(LCL=-10A\), \(UCL=10A\) - For suffix
lower-current-limit-control
refselect=U, \(U=0V\), \(I=1A\), \(LVL=1V\), \(UVL=4V\), \(LCL=+1A\), \(UCL=+10A\) - For suffix
upper-current-limit-control
refselect=U, \(U=4V\), \(I=1A\), \(LVL=1V\), \(UVL=4V\), \(LCL=+1A\), \(UCL=+10A\)
- For suffix
- Measure Current
- Output current with multimeter \(I_{out,multi}\)
- Output current with internal adc via spi \(I_{out,spi}\)
- Power off supply voltage
- Test passed if
- For suffix
current-control0
\(I_{out,multi} \in I_{out,adc} \pm 1A\) \(I_{out,multi} \in 0A \pm 1A\) - For suffix
current-control-20
\(I_{out,multi} \in I_{out,adc} \pm 1A\) \(I_{out,multi} \in -20A \pm 1A\) - For suffix
current-control+20
\(I_{out,multi} \in I_{out,adc} \pm 1A\) \(I_{out,multi} \in +20A \pm 1A\) - For suffix
lower-current-limit-control
\(I_{out,multi} \in I_{out,adc} \pm 1A\) \(I_{out,multi} \in +1A \pm 1A\) - For suffix
upper-current-limit-control
\(I_{out,multi} \in I_{out,adc} \pm 1A\) \(I_{out,multi} \in +10A \pm 1A\)
- For suffix