EPC901 Datasheet, PDF (29/37 Pages) Espros Photonics corp – CCD line sensor 1024x1 pixel

12. Power consumption considerations
12.1. General considerations
There are several options to control the power consumption. However, a tradeoff between performance and power consumption has to be
considered. The following section describes the various options. The most power-consuming blocks are
• Temperature sensors (approx. 3mA)
• Video amplifier (approx. 3.5mA)
• Charge pump and 5V regulator (approx. 13.5mA)
The wake-up time of the video amp is typ. 3µs only. Thus, in most applications it can be turned off during illumination in order to reduce the
average power consumption.
12.2. Low power operation with external 3V and 5V supply
The lowest possible power consumption of the epc901 can be achieved if it is supplied with 3V and 5V since the highest power consump-
tion is the internal charge pump which generates the 5V from VDD. In this case, the chip-internal charge pump and the internal 5V regu -
lator shall be turned off. The power consumption in this configuration is less than 20mW compared to 80mW in the standard mode. The
following application information shows how this can be achieved. Follow carefully the instructions in order to avoid damage of the chip.
Use protection diodes according to circuit diagram below. The diodes have to be low voltage Schottky devices with a forward current of at
least 100mA (i.e. BAT74).
IN_+3.0V
Ext. supply
+3.0V
IN_+5.0V
D1
Ext. supply
+5.0V
D3
D2
26
epc 901
VDD_1V8
32
VDD_5V0
18
VDD_7V0
20
VDD_OA
10
31
1 16
7
GND
Common GND
connection
Make sure that external 5V supply (VDD_5V0) is delayed by at least 100µs to the VDD.
1. Power up VDD (3V)
2. Wait for at least 100µs
3. Power up VDD_5V0
VDD
Common AGN
connection
VDD_5V0
Write the following sequence into the chip:
• Address 0xD0: ANA_TEST_MODE_EN_0 = 0x4a
• Address 0xD1: ANA_TEST_MODE_EN_1 = 0x66
• Address 0xD6: FORCE_ANA_CTRL_SIGS = 0x03
>100µs
//release register write protection
//release register write protection
//disable charge pump and 5V regulator
Important Note: The write access – as described above - has to occur as a sequence, no other read or write access is allowed in between
(no auto read)!
© 2016 ESPROS Photonics Corporation
Characteristics subject to change without notice
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Datasheet_epc901-V5.6
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