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