Power Switch Implementation; Cardbus Power Switch; Typical Power Switch Configuration; Figure 5. Power Switch Implementation - Texas Instruments PCI7620 Implementation Manual

3 Power Switch Implementation

3.1 CardBus Power Switch

The PCIXX20 controller can be used with any of the dual-slot TPS2228 and TPS222x
(TPS2226, TPS2226A, TPS2224, TPS2224A, TPS2223, and TPS2223A) family of power
switches. As shown in Table 4, bit 10 (12_SW_SEL) in the general control register at PCI
configuration offset 86h can be configured to select the power switch that is implemented. The
TPS222x dual-slot power switch is available in a pin-compatible (30-pin) package that allows
system designers the ability to provide for either voltage level in a single design.
LATCH
\CLOCK
DATA
SYSTEM5V
C1 C2
10uF 0.1uF
SYSTEM1.8V
C5 C6
10uF 0.1uF
1. R1 is used only if CLOCK is
generated internally, CLOCK generation
is determined by P2CCLK bit in the
System Control Register (PCI offset 80h,
it 27)
CLOCK
1
2
DATA
3
CLOCK
4
LATCH
5
6
7
8
SOCKETA_Vpp
9
10
11
SOCKETA_Vcc
12
13
14
15
Figure 5. Power Switch Implementation
Table 4.

Typical Power Switch Configuration

Voltage Requirement
1.8 V, 3.3 V, 5 V
3.3 V, 5 V, 12 V
PCI7620/PCI7420/PCI6620/PCI6420 Implementation Guide
R1 47K
U2
5VIN 5VIN
5VIN NC
DATA 1.8VIN
CLOCK NC
LATCH NC
1.8VIN SHDN#
NC NC
AVPP/AVCORE BVPP/BVCORE
AVCC BVCC
AVCC BVCC
AVCC BVCC
GND NC
NC OC#
RESET# 3.3VIN
3.3VIN 3.3VIN
TPS2228 (DB)
Power Switch 12V_SW_SEL
TPS2228
(recommended)
TPS222x
C4
0.1uF
30
29
28
27
26
25
24
23
SOCKETB_Vpp
22
21
20
SOCKETB_Vcc
19
18
17
16
C10
0.1uF
0
1
SCPU019
SY STEM12V
C3
10uF
SY STEM3.3V
C9
10uF
11