44.1.1 Overview
A simplified block diagram for the USB Voltage Regulator module is shown below.
STANDBY
reg33_in
reg33_out
Yes
No
RUN Regulator
STANDBY Regulator
Voltage Regulator
Chip
Power
Supply
Regulated Output
Voltage
Voltage Regulator
ESR: 5m -> 100m Ohms
External Capacitor
typical = 2.2uF
Other Modules
Figure 44-2. USB Voltage Regulator Block Diagram
This module uses 2 regulators in parallel. In run mode, the RUN regulator with the
bandgap voltage reference is enabled and can provide up to 120 mA load current. In run
mode, the STANDBY regulator and the low power reference are also enabled, but a
switch disconnects its output from the external pin. In STANDBY mode, the RUN
regulator is disabled and the STANDBY regulator output is connected to the external pin.
Internal power mode signals control whether the module is in RUN or STANDBY mode.
44.1.2
Features
• Low drop-out linear voltage regulator with one power channel (3.3 V).
• Low drop-out voltage: 300 mV.
• Output current: 120 mA.
• Three different power modes: RUN, STANDBY and SHUTDOWN.
• Low quiescent current in RUN mode.
• Typical value is around 120 µA (one thousand times smaller than the maximum
load current).
• Very low quiescent current in STANDBY mode.
• Typical value is around 1 µA.
• Automatic current limiting if the load current is greater than 290 mA.
Introduction
K22F Sub-Family Reference Manual, Rev. 4, 08/2016
1120 NXP Semiconductors
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