Datascope Passport - Mindray
Datascope Passport - Mindray
Datascope Passport - Mindray
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Theory of Operation Power Supply<br />
On the Front End processor, it is crucial during power up that VDD never exceeds VDDH by<br />
more than 0.3V. Within the processor, there are diode devices between the two voltage<br />
domains, and violating this rule can lead to a latch-up condition. This is satisfied because it's<br />
3.3V switching power supply runs off of +5.5V and has a slower startup, while VDDH, which<br />
also runs off of +5.5V, is output from the voltage regulator, which comes up almost<br />
immediately. So VDD will never exceed VDDH. Contingencies for enabling the +5V and -5V<br />
by the microcontroller were removed to satisfy the power up sequencing on the VDDH line.<br />
2.10.2 Part Number 0014-00-0251<br />
The power supply can operate off of an AC line, a DC source from the Docking Station (DS-<br />
DC), or two Batteries (either Sealed Lead Acid or Lithium-Ion). The power supply will<br />
automatically select the available power source based on a specified priority.<br />
The power supply provides 5V and 12V regulated DC output voltages. The outputs are<br />
turned On/Off via a logic signal REMOTE-ON*.<br />
Two independent multi-chemistry battery chargers are included in the power supply. The<br />
chargers are capable of rapid charging up to two Sealed Lead Acid or Lithium-Ion batteries.<br />
The chargers will be activated when AC or DS-DC power is applied.<br />
The power supply constantly monitors various available power sources, which are selected in<br />
the following priority order:<br />
1. AC, or DS-DC<br />
2. BATTERY<br />
The total off-state current from both batteries must be less than 5 mA. During Battery<br />
operation, the BATT-OP* output signal is set to a logic “0”. Otherwise, BATT-OP* is a logic<br />
“1”. When operating on battery power, each battery will share the total load based on its<br />
individual charge level.<br />
The transfer from one source to another is seamless and occurs when the source providing<br />
power is either disconnected or out of range.<br />
An AC-PRESENT output signal that can drive an external LED at 10mA indicates the<br />
presence of AC power. When AC power is applied, this output signal has an open-circuit<br />
voltage of 20Vdc ±15%, with output equivalent impedance of 1.8kΩ ±10%. When AC<br />
power is not present, the AC-PRESENT output signal is 0V.<br />
The power supply includes two independent chargers that are capable of charging 2 Lithium-<br />
Ion (Li-ion) batteries (P/N: 0146-00-0069) or 2 Sealed Lead Acid (SLA) batteries (P/N:<br />
0146-00-0043).<br />
The chargers are enabled upon application of AC, or DS-DC power and are independent of<br />
the REMOTE-ON signal. The charger provides protection against shorted battery cells and<br />
overly discharged batteries.<br />
<strong>Passport</strong> 2®/<strong>Passport</strong> 2 LT Service Manual 0070-10-0441 2 - 37