Datasheet

Vybrid Power Consumption and Options, Rev. 0
Freescale Semiconductor 11
Powering options
• External DC/DC converter
8.3 External ballast transistor powered from VDD (default)
The recommended circuit for general purpose application uses an external ballast transistor, which is
powered from 3.3V to create a 1.2V power supply. This solution simple and suitable for a wide range of
applications, but is very low-efficiency. Its simplicity is demonstrated in particular in the case that
SDRAM memory is not used. The solution is also used on the Vybrid Freescale Tower module.
Figure 4. External ballast transistor powered from VDD
The block scheme of the power supply solution using the external ballast transistor powered from VDD
on 3.3V voltage level is captured in Figure 4.
8.3.1 Power efficiency considerations
In this power option, the Vybrid SoC uses an internal control LDO circuit with external ballast transistor
for normal run power mode. This solution creates 1.2V power supply voltage for the core and Video ADC
analog front end using the external ballast transistor. As shown in Figure 3 and Figure 4, the transistor is
powered from 3.3V power rail.
In OOBE demo use case core current is 289mA.
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