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(No.RA021<Rev.001>)1-5
2.2
CIRCUIT DESCRIPTION
2.2.1 KRK-14H
2.2.1.1
Overview
KRK-14H is an optional unit designed to separate the Mobile transceiver and Basic type panel (KCH-19) by remote control cable (KCT-
71). KRK-14H communicates with Mobile transceiver in a serial bus and controls Basic type panel. This unit consists of a power supply
circuit, audio circuit, and control circuit.
2.2.1.2
Power supply circuit
SB (SwB Power) is supplied from Mobile transceiver via CN1. IC1, IC2, A1, and IC4 are step down switching regulator. IC1
regulates 5.3V (53DC) from SB. 53DC is the power source of D-class audio amplifier, CAN transceiver, and regulator (IC6). IC6 reg-
ulates 5.0V (50D). 50D is supplied to level shift circuits and a part of audio circuits. IC2 regulates 3.9V (39DC) from SB. 39DC is the
power source of regulators (A1, IC3, IC4, and IC5). A1 regulates 1.2V (12D), IC4 regulates 1.8V (18D), IC3 regulates 3.3V (33A), and
IC5 regulates 3.3V (33D).
12D is supplied to MPU core. 18D is supplied to MPU, Mobile DDR, Codec DSP core, In MPU memory interface work with 1.8V power
supply (18D). The I/O section of the NOR flash memory works with a 1.8V power supply. It must be supplied after 33D is powered up.
Therefore, the 1.8V power supply of flash memory is supplied through switch IC (IC7) which is controlled by 33D. 33A is the power
source of audio circuits. Those are operational amplifiers and the analogue section in Codec IC. 33D is the power source of I/O section
of MPU, Codec, and CAN transceiver. The power source of flash memory is 33D, too. During the SB supplies, all regulators work.
Fig.1 Power supply circuit
CN1
CN35 (Basic type panel)
IC1
5.3V DC/DC
Class-D Audio amplifier,
CAN transceiver
IC6
5V AVR
Level shift circuits,
Audio circuits
IC2
3.9V DC/DC
IC4
1.8V DC/DC
A1
1.2V DC/DC
MPU core
MPU, Mobile DDR,
Codec DSP
IC7
Switch
Flash memory
Q2
Level shift
IC5
3.3V AVR
MPU I/O, Codec I/O,
CAN transceiver,
Flash memory
IC3
3.3V AVR
Audio circuits,
Codec Analog section
SB
12D
53DC
18D
39DC
33D
18D
18D
33A
33D
18D_Flash
18D
12D
50D
Содержание KRK-14H
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Страница 32: ... No RA021 Rev 001 VSE Printed in Japan JVC KENWOOD Corporation Communications Systems BU ...