Installation Instructions

Table Of Contents

Contribution to Technology · ZLG Electronics

A6G2C Series Core Board

MiniARM Core Board

Product Data Manual

Figure 4.8 USB power switching circuit for discrete devices

The advantage of the circuit in Figure 4.8 is that it is composed of discrete MOS transistors and can pass a

larger current. It can be used in the occasions where the USB port is connected to an external GPS, 3G or 4G

module with high current startup. In addition, discrete devices are cheaper than integrated USB power

management chips. The disadvantage is that you need to manually switch between Device and Host.

The USB detection of the i.MX6UL needs to identify two signals, ID and VBUS. The power of VBUS

and Host are on the same circuit. In the case of detection USB device identification, VBUS needs to have a

changing state. Therefore, it is not advisable to connect capacitors with large capacity in parallel on the VBUS to

prevent the discharge of the capacitors from being completed and the failure of next identification.

The USB power management chip SP2526A-1EN-L can be used for switching when the USB port is used in

the occasions where the current is not high and the price requirements are not strict. Figure 4.9 shows the

reference circuit.

ESD protection must be

placed at the interface, the

resistor should be behind

MicroUSB socket

Disconnect -> OTG1 used as Device,

default

Short-circuit -> OTG2 used as Host