12-V Voice Coil Motor Driver
FEATURES
D 1.8-A H-Bridge Output D Class B Linear Operation
D Externally Programmable Gain and Bandwidth
D Undervoltage Head Retract D Programmable Retract Current D Low Standby Current D Rail-to-Rail Output Swing D Single 12-V Supply D System Voltage Monitor with Fault Output
DESCRIPTION
The Si9961A is a linear actuator (voice coil motor) driver
suitable for u in disk drive head positioning systems. The Si9961A contains all of the power and control circuitry necessary to drive the VCM that is typically found in 31/2-inch hard disk drives and optical disk drives. The driver is capable of delivering 1.8 A at a nominal supply of 12 V.
The Si9961A provides all necessary functions including a motor current n amplifier, a loop compensation amplifier and a power amplifier featuring four complementary MOSFETs in a H-bridge configuration. The output crossover protection ensures no cross-conducting current and true Class
B operation during linear tracking. Externally programmable gain switch at the input summing junction increas the resolution and dynamic range for a given DAC. The head retract circuitry can be activated by either an undervoltage condition or an external command. An external resistor is required to t the VCM current during retract.
The Si9961A is constructed on a lf-isolated BiC/DMOS power IC process. The IC is available in both standard and lead (Pb)-free, 24-pin SO packages for operation over the commercial, C suffix (0 to 70_C) temperature range.
FUNCTIONAL BLOCK DIAGRAM
OA2
IA2−
FAULT
RETRACT
INH INL V CC
EXT OUTPUT
A SENSE IN+SENSE IN −
I RET FB
GAIN SELECT
SENSE OUT OUTPUT
B
Enable
ABSOLUTE MAXIMUM RATINGS
Voltages Referenced to Common Pin
V+ Supply Range −0.3 V to 16 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pin (FAULT) −0.3 V to V CC + 0.3 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pin (Output A & B, Source A & B) −0.3 V to V DD + 0.3 V . . . . . . . . . . . . . . . . Pin (All Others) −0.3 V to V+ + 0.3 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Maximum Clamp Current
Output A, Output B (Puld 10 ms at 10% duty cycle)"1.8 A . . . . . . . . . . . . Pin (All Others) "20 mA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Storage Temperature −65 to 150_C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operating Temperature 0 to 70_C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Junction Temperature (T J )150_C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power Dissipation (Package)a
24-Pin SOIC b 3.125 W . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Thermal Impedance (Q JA )a
24-Pin SOIC 40_C/W . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Notes
a.Device mounted with all leads soldered or welded to PC board.
b.Derate 25 mW/_C above 25_C.
SPECIFICATIONS
Test Conditions
Unless Otherwi Specified
V+ = 12 V 10% V = 116 V Limits
C Suffix 0 to 70_C
Parameter
Symbol沛沛
"10%, V DD = 11.6 V "10%V CC = 5 V "10%, V REF − = GND = 0 V
V REF = 5 V "5%
Min b Typ a Max b
Unit
Bridge Outputs (A 4, A 5)
High Level Output Voltage V OH I OH = 1.0 A, V DD = 10.2 V, OA 2= V REF "1 V
6s是什么意思8.0
gum9.1Low Level Output Voltage V OL I OL = −1.0 A, OA 2 = V REF "1 V 0.6
1.1V
Clamp Diode Voltage V CL
I F = 1.0 A, ENABLE = High 2.5Amplifier Gain
Output V RANGE = V REF "2 V
12
1618
V/V Dynamic Crossover Current Measured at V DD
10
mA Slew Rate
SR 1
V/m S Small Signal Bandwidth (−3 dB)0.2
MHz Input Deadband
−60
60
mV A 2, Loop Compensation Amplifier
Input Offt Voltage V OS −88mV Input Bias Current I B
Gain Select = High, IA 2− = 5 V −50
50
nA Unity Gain Bandwidth R LOAD = 10 k W , C LOAD = 100 pF to V REF
1
越狱 第二季MHz Slew Rate
SR 1
awkward什么意思
平安夜快乐英文V/m s Power Supply Rejection Ratio PSRR @ 10 kHz
50Open Loop Voltage Gain A VOL 80
dB Output Voltage Swing
V O
R LOAD = 10 k W to V REF
V REF −2
V REF +2
V
A 3, Current Sen Amplifier
Input Offt Voltage V OS −5
5
mV Input Impedance
R IN
I SENSE IN+ to I SENSE IN −
5k W Small Signal Bandwidth (−3 dB)R LOAD = 10 k W , C LOAD = 100 pF to V REF
1MHz Common Mode Rejection Ratio CMRR @ 5 kHz
50
dB Slew Rate SR 2V/m s Gain
3.94
4.1V/V Input Common-Mode Voltage Range V CM To GND
−0.32Output Voltage Swing
V O
R LOAD = 10 k W , C LOAD = 100 pF to V REF
V REF −2
V REF +2
V
Supply
I CC
Static, No Load 0.01Supply Current (Normal)
I V+,RETRACT = High 25mA
I DD
g ENABLE = Low
5
2012年6月英语六级真题13
SPECIFICATIONS
Limits
电脑常见故障C Suffix 0 to 70_C
Test Conditions
V+ = 12 V Parameter
Unit
Max b Typ a Min b Unless Otherwi Specified
"10%, V DD = 11.6 V "10%
V CC = 5 V "10%, V REF − = GND = 0 V
V REF = 5 V "5%
Symbol
Supply
I CC
Static, No Load 0.01Supply Current (Standby)
I V+,RETRACT = High 0.20.4mA
I DD
g ENABLE = High 0.8 1.6Normal Mode 10.211.6
13.2V DD Range V DD Retract Mode
2.014V CC Range V CC 4.55 5.5V V+ Range
V+
10.8
1213.2
Gain Select Switch
R FB Switch Resistance 108240R INH Switch Resistance IA2− = 5 V
135300W
R INL Switch Resistance
810
1800
V REF (EXT)
Input Current
I REF OA2 = V REF
0.150.400.65mA External Voltage Range小情歌英文版
V REF
4.75
5
5.25
V
Power Supply Monitor
V CC Undervoltage Threshold V REF = 5.0 V
3.82
4.12 4.42
V Hysteresis
40mV V+ Undervoltage Threshold V REF = 5.0 V
9.1
9.810.6V Hysteresis
100
mV
Gain Select, RETRACT, ENABLE Input
Input High Voltage V IH 3.5
Input Low Voltage V IL 1.5V
Input High Current I IH V IN = 5 V −11Input Low Current
I IL
V IN = 0 V
−11
m A
FAULT Output
Output High Voltage V OH I OH = −100 m A V CC −0.8
V CC −0.33V
Output Low Voltage
V OL I OL = 1.6 mA 0.250.50Output High Sourcing Current
rbwI OHS
V OUT = 0 V
400
1100
m A RETRACT Current Control (RETRACT = Low, Output Current from A to B)
I RET Bias Voltage
V(I RET )V DD = 10 V, R RET = 3.74 k W 0.66
Retract Output Pull-Up Voltage V OUT A V DD = 2.5 V to 14 V, I OUTA = 30 mA V DD −1V
Retract Output Pull-Down Current I OUTB V DD = 10 V, V OUTB = 5 V R RET = 3.74 k W
R SB = 0.5 W , T A = 25_C 2230
38
Maximum Emergency Retract Current I OUTB (Max)
V DD = 2 V, V OUTB = 0.7 V R RET = < 10 W , R SB = 0.5 W ,
40
mA
Retract Current V DD Supply Rejection Ratio V DD = 2 V to 14 V, R RET = 3.74 k W 3.0%/V Retract Current Temperature Coefficient
V DD = 10 V, R RET = 3.74 k W
−0.3
%/_C
Notes
a.Typical values are for DESIGN AID ONLY , not guaranteed nor subject to production testing.
b.The algebraic convention whereby the most negative value is a minimum and the most positive a maximum.
R INH R FB R INL
IA2−I SENSE OUT
OA2FAULT 21I SENSE (IN)−V CC I RET
EXT V REF
SOURCE B OUTPUT B
V DD (Spindle Supply)
V+
OUTPUT A RETRACT
GND GAIN SELECT SOURCE A ENABLE GND V REF −I SENSE (IN)+
24-Pin SOIC (Wide Body)
22232423411819205671781415169
10
1113
12
Top View
PIN CONFIGURATION AND ORDERING INFORMATION
ORDERING INFORMATION
Part Number
Lead (Pb)-Free Part Number Temperature Range
Package
Si9961ACY Si9961ACY -T1
Si9961ACY -T1—E3
0 to 70_C
SOIC-24(Wide Body)
APPLICATIONS
Introduction
The Si9961A Voice Coil Motor (VCM) driver integrates the active feedback and drive components of a head-positioning rvo loop for high-performance hard-disk applications. The Si9961A operates from a 12-V ("10%) power supply and delivers 1 A of steady-state output current. This device is made possible by a power IC process which combines bipolar,CMOS and complimentary DMOS technologies. CMOS logic and linear components minimize power consumption, bipolar front-ends on critical amplifiers provide necessary accuracy,and complimentary (p- and n-channel) DMOS devices allow the transconductance output amplifier to operate from ground to V DD . Two ur-programmable, current feedback/input voltage ratios may be digitally lected to optimize gain for both ek and track following modes, to maximize system accuracy for a given DAC resolution. An undervoltage lockout circuit monitors the V+ supply and generates a fault signal to trigger an orderly head-retract quence at a voltage level sufficient to allow the spindle motor’s back EMF-generated voltage to supply the necessary head parking energy. Head input. VCM current during retract can be ur programmed with a single external resistor. External components are limited to R/C filter components for loop compensation and the resistors that are required to program gain, retract curre
nt, and the load current n.
Ur-Programmable Gains
During linear operation, the transconductance amplifiers’gains (input voltage at V IN vs. VCM current, in Figure 1) are t by external resistors R 3 ! R 5, R SA , and R SB and lected by gain input. After lecting a value for R SA and R SB that will yield the desired VCM current level, the High and Low feedback gain ratios may be determined by the following:
(GAIN SELECT Input = High)
High Gain +
ǒR 5R 314R S (GAIN SELECT Input = Low)
Low Gain +
ǒR 5R 4
Ǔ
14R S
Where R S = R SA = R SB
Input offt current may then be calculated as:
I OS
+14R
S
ǒ
ǒR S
)R IN ǓR IN Ǔ
ǒ
V OSA2
)
5V IAS3ǓWhere R IN = R 3 or R 4
FIGURE 1.Si9961A Typical Application
Head Retract
A low on the RETRACT input pin turns output devices Q1 and
Q4 on, and output devices Q2 and Q3 off. Maximum VCM
current can be t during head retract by adding an external
resistor between the IRET pin and ground. Maximum retract
current may be calculated as:
I OUT+175x I ret+175x 0.66V R ret
Head retract can be initiated automatically by an undervoltage condition (either the 12-V or 5-V supplies on the Si9961A) by connecting the FAULT output to the RETRACT input.
A high ENABLE input puts both driver outputs in a high-impedance state. The ENABLE function can be ud to eliminate quiescent output current when power is applied but the head has been parked,
such as a sleep mode. A sleep-mode power down quence should be preceded by a retract signal since a power failure during this state may not provide adequate spindle-motor back EMF to permit head retraction.
Transconductance Amplifier Compensation
The Si9961A features an integrated transconductance amplifier to drive the voice coil motor (VCM). T o ensure proper operation, this amplifier must be compensated specifically for the VCM being driven. As a first approximation, the torque constant and inertia of the VCM may be ignored, although they will have some influence on the final results, especially if large values are involved. (See Figure 1.)
