AN1056

Application Note 1056
The Design Guide for AM4963/AM4963R
Prepared by Zhihong Zhang
Design Engineering Dept.
good heat dissipation ability. D2 and D3 are
recommended to be used when the average current in
coil L1 is higher than 300mA. A typical PCB
application example is shown in Figure 1.
1. Introduction
The AM4963/AM4963R is a full wave driver IC with
direct PWM control function and thermal resistor
control function. It is used for single phase motor and
is capable of speed control by PWM pulse and
thermal resistor at the same time. The
AM4963/AM4963R is featured by:
•
•
•
•
•
•
•
•
•
•
•
•
The Motor Speed is Controlled by PWM Pulse
Directly and Thermal Resistor at The Same
Time
Low Corner Temperature (30°C) Adjustable
High Corner Temperature (38°C) Adjustable
Full Speed when Thermal Resistor Shorten
Built-in Triangle Wave Circuit without Extra
Oscillation Capacitor
Built-in Minimal Speed Setup Circuit
Alpha Slope Adjustable
Rotation Speed Indicator (FG)
Rotation/lock State Indicator (RD)
Built-in Temperature Control Circuit
Built-in Thermal Shutdown Circuit
Lock Protection and Auto-restart
Figure 1. PCB Drawing
3.3 Measure Parameter
Solder D1, C1, C2, C3 , RT(TSM2A103F39H1RZ),
R8 (8.03k for 30°C), R9(160k for 38°C) ,R7 (5.1k)
Hall sensor onto the PCB (R1, R2, R3, R4, R5, R6
open); Measure the fan rotating speed vs. input duty
and temperature. Draw a curve figure accordingly
(Step=5%), as Figure 2, 3.
This application note involves the general description,
recommended application steps and typical
application examples, which may be helpful to
designers in product development process.
2. General Description
The AM4963/AM4963R is capable of speed control
by PWM pulse. It can be used in applications such as
CPU cooler fan in PC and brushless DC motor driver.
100
VCC=12V
The AM4963/AM4963R is available in HTSSOP-14
and SSOP-16 packages.
Output Duty Cycle (%)
3. Recommended Application Steps
3.1 Set Up Specification
Create a specification for the fan rotating speed vs.
input duty and temperature; draw a curve figure
accordingly (Figure 2, 3).
O
TA=38 C
60
40
20
0
3.2 Create PCB Drawing
Make a PCB drawing in accordance with the
recommended application circuit, as shown in Figure
1. The soldering pad area contacted with the power
ground pin should be as large as possible to ensure
Dec. 2010
O
TA=30 C
80
0
20
40
60
80
100
Input Duty Cycle (%)
Figure 2. Output Duty Cycle vs. Input Duty Cycle
(VCC=12V; TA=30°C, 38°C)
Rev. 1. 0
BCD Semiconductor Manufacturing Limited
1
Application Note 1056
100
VCC
D1
L1
V+
D2
Output Duty (%)
80
C1
1 F
R1
OUT1
TH
OUT2
3
VCC
4
VMIN
SGND
CT
5
R3
R2
60
6
7
C3
1 F
40
D3
AM4963/AM4963R
2
R4
8
PWM
RADJ
CF
HIN-
FG/RD
HIN+
TL
RT
PGND
RT
16
15
R9
V+
14
R5
13
C2 0.47 F
12
11
R6
R11
10
9
R8
1
0
28
30
32
34
36
38
V+
AH921
Input Duty Cycle=0%
Input Duty Cycle=20%
Input Duty Cycle=50%
Input Duty Cycle=70%
Input Duty Cycle=100%
20
R10
Figure 7. Typical Application of AM4963/AM4963R
with AH921 Hall Sensor (Application Circuit for
SSOP-16 Package)
40
o
TA ( C)
Figure 3. Output Duty Cycle vs. TA
Note 1: The package type of AH921 used here is
SOT-23-3, if TO-92S-3 is used, please swap the
connection of HIN- and HIN+.
3.4 Adjust Low Corner Temperature
RT=TSM2A103F39H1RZ
38
0
Low Corner Temperature ( C)
40
Figure 4. Typical Application of AM4963/AM4963R
(Application Circuit for HTSSOP-14 Package)
36
34
32
30
28
26
24
5
6
7
8
9
10
R8 (kΩ)
Figure 8. Low Corner Temperature vs. R8
3.5 Adjust High Corner Temperature
TH can be expressed as below: TH=TL+5*R9/100.
42
Input duty cycle=100%
0
TL=30 C
40
O
High Corner Temperature ( C)
Figure 5. Typical Application of AM4963/AM4963R
(Application Circuit for SSOP-16 Package)
38
36
34
32
40
80
100
120
140
160
180
200
220
240
R9 (kΩ)
Figure 6. Typical Application of AM4963/AM4963R
with AH921 Hall Sensor (Application Circuit for
HTSSOP-14 Package)
Dec. 2010
60
Figure 9. High Corner Temperature vs. R9 (Note 2)
Rev. 1. 0
BCD Semiconductor Manufacturing Limited
2
Application Note 1056
Note 2:
1) Low corner temperature (TL) is set by thermal
resistor RT and R8; RT=R8 when at temperature TL.
2) High corner temperature (TH) can be expressed as:
TH≈TL+5*R9/100k.
3) First, set TL, then TH.
(2) Adjust the maximum speed vs. input duty to
approximately match the target specification via R3
and R4 at high temperature (T>TH, VRT>VFG/RD
+0.7V)
3.6 Adjust Maximum Speed
(1) First, adjust the maximum speed vs. input duty to
approximately match the target specification via R3
and R4 at low temperature (T<TL, VRT<VFG/RD);
Measure the fan rotating speed vs. input duty. And
draw a curve figure accordingly (Step=5%).
100
Output Duty Cycle (%)
100
Output Duty Cycle (%)
60
40
20
R3=360k
R3=1M
R3 Open
80
R3=360k
R3=1M
R3 Open
80
0
0
20
40
60
80
100
Input Duty Cycle (%)
60
40
20
100
0
0
20
40
60
80
100
80
Output Duty Cycle (%)
Input Duty Cycle (%)
100
Output Duty Cycle (%)
80
60
40
R4=150k
R4=390k
R4 Open
20
60
0
0
40
20
40
60
80
100
Input Duty Cycle(%)
R4=150k
R4=390k
R4 Open
20
0
0
20
40
60
80
Figure 11. Output Duty Cycle vs. Input Duty Cycle at
High Temperature (R3=360k, 1M, Open; R4=150k,
390k, Open)
100
Input Duty Cycle (%)
Figure 10. Output Duty Cycle vs. Input Duty Cycle at
Low Temperature (R3=360k, 1M, Open; R4=150k,
390k, Open)
Dec. 2010
Rev. 1. 0
BCD Semiconductor Manufacturing Limited
3
Application Note 1056
3.8 Adjust Minimum Speed
Adjust the minimum speed vs. input duty to
approximately match the target specification via R2
(R1=15kΩ). Measure the fan rotating speed and the
input duty, as shown in Figure 13.
3.7 Adjust Slope k
Adjust slope k of the fan rotating speed vs. input duty
to approximately match the target specification via
R5 and R6; Measure the fan rotating speed vs. input
duty. And draw a curve figure accordingly, as shown
in Figure 12.
100
R6=100k
R6=270k
R6 Open
100
60
80
Output Duty Cycle (%)
Output Duty Cycle (%)
80
40
20
0
60
40
20
0
20
40
60
80
100
Input Duty Cycle (%)
100
0
80
Output Duty Cycle (%)
0
R5=100k
R5=270k
R5 Open
2
4
6
8
10
R2 (kΩ)
60
Figure 13. Output Duty Cycle vs. R2
40
20
0
0
20
40
60
80
100
Input Duty Cycle (%)
Figure 12. Output Duty Cycle vs. Input Duty Cycle (R5,
R6=100k, 270k, Open)
Dec. 2010
Rev. 1. 0
BCD Semiconductor Manufacturing Limited
4
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