Portable b-power overall design (1)

Portable ultrasound system for internal use of the power supply is more complex, the external adapter and battery power DC/DC must be converted to convert the voltage of the system needs.

In order to reduce the power consumption of useless, increase the efficient use of battery, the system board, b-control panel, LCD monitor and keyboard power switching power supply.

Portable b-power 1 overall design for portable b-power block diagram of the overall design.

Portable b-power supply input voltage in two ways: first, the power adapter input voltage to 18V, battery input, voltage-14.4V. Requirements for two voltages between the thermal switch and switch the voltage does not affect the system work, i.e. providing electric and battery-powered no-latency thermal switch function. Required output ± 12V, 5V, 3.3V, ± several voltage 48V, specific indicators to 12V/2.5A,-12V/4A 0.5A, 5V/3A, 3.3V/, + 48V/80mA,-48V/80mA. With single-button switch machine function, i.e., radio, press the power key to turn on the power; when the power, press the power key to the control panel sends the signal to shut down, the host computer can also shut down through the software (i.e. supported ATX shutdown command). Power output interface using standard computer ATX connector.

Figure 1 portable b-power overall design block diagram

Power switch circuit design portable b-power switch circuit shown in Figure 2, the external power adapter, voltage input AC 18V, VD100, VD101 diode, then by R100, R107 divider to N100A (LM193) voltage comparator of 3 feet (phase).

Battery voltage is 14.4V, R101, R108 partial pressure added to N100A (LM193) voltage comparator 2 feet (reverse side). As 3 feet voltage greater than 2 feet, thus N100A (LM193) 1 foot output, transistor breakover, V101 as V100, field effect tube V105 POWER_IN + side up, get is the external power adapter 18V voltage. When no external power adapter, or portable ultrasound machine used in the process, external AC power suddenly cause unable to use the external power adapter, N100A (LM193) 3 feet voltage of less than 2 feet, N100A (LM193) 1 foot output low level so that the transistor breakover ending, V101 V100, field effect tube V105 conduction. Battery voltage after conduction of FET V105 source, drain, POWER_IN + end get battery 14.4V voltage, two voltages between the thermal switch. VD102, played in circuit VD103 isolation, quarantine, external power adapter and the battery.

Figure 2 power switching circuit

Single-touch switch machine circuit design portable b-single-touch switch machine electric circuit as shown in Figure 3, the add-in adapter or batteries to POWER_IN + voltage, rushed to the scene effects tube Q100, ready to post, all the way through R104, VD104 sent to touch button POWER-KEY2.

Touch button POWER-KEY2 is grounded on the other end, when you press the touch button POWER-KEY2 N106, transistor's base electrode is clamped at low level, the N106 breakover, then N102 also breakover, field effect tube Q100 breakover, by external adapter or batteries to POWER_IN + voltage after conduction of Q100 source, drain, voltage, POWER + to high and low voltage circuit power supply, power on the machine. At power on, POWER + 6V voltage after enabling the Zener diode, triode N104 breakover N104 collector for low level, the N106 breakover, keep the power-on status.

Figure 3 a single-touch switch machine circuit

When portable ultrasound machine turned on, then press the button once, the optical coupling POWER-KEY2 B101 via the optical coupling secondary breakover, inverter output of 4 feet D101 low level to the Control Panel, control panel to issue low-level shutdown command, the optical coupling POWER-OFF1 B100 breakover, thereby enabling triode N103 breakover, set up, the N104 N104 electrode high level as the N106, field effect tube Q100 as for shutdown.

When the PC shutdown issue high level commands POWER-OFF, would also enable the optical coupling B100 breakover, the rest of the process and the control panel as the shutdown process. Low voltage power circuit design portable B ultra low voltage power circuit shown in Figure 4, there are six TI company TPS5430 and 1 composed of United States national LM2576. 6 TPS5430 provides 2 group + 12V, + 5V, + glow voltage, one set to portable ultrasound machine master Board power supply, another group is used to portable b-computer power supply. These two groups are identical, therefore, we only give one set of electricity principle diagram. LM2576 is responsible for producing-12V voltage to a portable computer in a b-.

Figure 4 low voltage power circuit