Download Brief Description of TEM-PS Schematic

Brief Description of TEM-PS Schematic
G. Haller
V2
9/19/03
Top-Sheet:
On the left side is the connector to the LAT-Power Distribution Unit. 28V power is
incoming from the PDU, some voltage and temperature monitoring signals are output.
The 28V is filtered (MIL-461) in the filter block and connected to four main blocks
 Calorimeter switch block. Here the 28V to the calorimeter supplies is
enabled/disabled via an enable signal from the TEM DAQ board.
 Tracker switch block. Here the 28V to the tracker supplies is
enabled/disabled via an enable signal from the TEM DAQ board.
 Buck-Sync Block: in case the converters need to be synchronized, an
oscillator is incorporated in the board
 DAQ power: generates 2.5V and 3.3V for TEM DAQ board
The switched calorimeter power is connected to the calorimeter low voltage block,
generating 3.3V analog and 3.3V digital voltages, and the high voltage block, generating
up to 100V (adjustable via a programmable analog voltage on the TEM DAQ board).
The switched tracker power is connected to the tracker low voltage block, generating
1.5V analog, 2.5V analog, 2.5V digital voltages, and the high voltage block, generating
up to 150V (adjustable via a programmable analog voltage on the TEM DAQ board).
The resistors on the top-level are used to derive the currents (total and for the HV
supplies) via ADC’s on the TEM DAQ board.
The connector on the right side is the TEM-DAQ board connector. The cal and tkr
voltages are connected via the TEM-DAQ board to the sub-systems.
CAL and TKR low-voltage sheets:
The sub-system voltages are generated from the 28V via MAX726 converters. At the
output an additional LC filter is added. The TKR 1.5V is generated by summing an
external reference voltage in the feed-back of the Maxim since the Maxim on-chip
reference is higher than 2V. The npn transistors are used to synchronize the converters.
DAQ sheet: Since the ACTEL 36S series FPGA’s (on the TEM DAQ board) require that
the 3.3V is applied delayed in respect to the 2.5V, a delay circuit is incorporated into the
DAQ block.
High-Voltage Supply Block:
The booster coil (330uH) is charged by the bipolar transistor Q504. Control of the onstate of Q504 is through Q501, Q502, off-state through Q505. These transistors are
driven by two non-overlapping pulses (N65, N67).
A voltage doubler stage D501, D507, D508 limits the voltage to each diode to 75V.
Modulation of the driving amplitude is done similarly to A. Ruitbergs design, through the
divider R507 and R508 in conjunction with the output of the feedback loop coming from
U504.