Datasheet UC3178 Datasheet (UNITRODE)

Page 1
The UC3178 ful l-bridge power amplifier, rated for continuous output current of 0.45 Amperes, i s intended for use in demanding servo applications. This device includes a preci sion current sense amplifier that senses load current with a single resistor in series with the load. The UC3178 is optimized to con ­sume a minimum of supply current , and is designed to operate in both 5V and 12V systems. The power output stages have a l ow saturation voltage and are protected with current limiting and thermal shutdown. When inhibited, the device will draw less than 1.5mA of total supply current.
Auxiliary functions on this device include a load current sensing and rectifica­tion function that can be configured with the device’s over-current comparator to provide tight control on the maximum commanded load current. The closed loop transconductance of the configured power amplifier can be switched be­tween a high and l ow ran ge wi th a single logic input. The 4:1 change in gain can be used to extend the dynamic range of the servo loop. Bandwidth vari­ations that would otherwise result with the gain change can be controlled w ith a compensation adjust pin.
This device is packaged a power PLCC, "QP" package which maintains a standard 28-pin outline, but with 7 pins along one edge directly tied to the die substrate for improved thermal performance.
查询UC3178供应商
Full Bridge Power Amplifier
UC3178
FEATURES
Precision Current Control
•±450mA Load Current
1.2V Typical Total Vsat at
Programmable Over-Current Control
Range Control for 4:1 Gain Change
Compensation Adjust Pin for Range Bandwidth Control
Inhibit Input and UVLO
3V to 15V Operation
12mA Quiescent Supply
Current
BLOCK DIAGRAM
DESCRIPTION
5/93
UDG-92010
Page 2
UC3178
Unless otherwise stat ed spe cifica tion s hold for TA = 0°C to 70°C, VC(+) = VIN(+) = 12V, REF Input = VIN(+)/2, O/C Inpu t & Inhibit Input = 0V.
ABSOLUTE MAXIMUM RATINGS
Input Supply Vo ltage, (VIN(+), VC(+) ). . . . . . . . . . . . . . . . . . 20V
O/C Sense, Log ic Input s, and REF Input
Maximum forced voltage. . . . . . . . . . . . . . . . . -0.3V to 10V
Maximum forced current . . . . . . . . . . . . . . . . . . . . . . ±10mA
A & B Amplifier Inputs . . . . . . . . . . . . . -0.3V to (V
IN(+) + 1.0V)
O/C Indicate O pen Collector Output Voltage. . . . . . . . . . . . 20V
A and B Output Cur ren ts(co nt in uous )
Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . Internally Limited
Sink . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.6A
Output Diode Cur re nt (pulse d)* . . . . . . . . . . . . . . . . . . . . . 0.5A
O/C Ind Output Current (c ont inuous) . . . . . . . . . . . . . . . . 20mA
Operating Jun ctio n Tem per atur e. . . . . . . . . . . . . . . . . . +150°C
Storage Temperature. . . . . . . . . . . . . . . . . . . -65°C to +150 °C
*Notes: Unless other wise indicat ed , voltag es are refer enc ed to ground and curre nts are posit ive into , negat ive out of , the speci­fied terminals, "Pu lsed" is defin ed as a less tha n 10% dut y cy­cle pulse with a maximum dura tion of 500
µs.
THERMAL DATA
QP package: (see pac kaging sect ion of UICC data book for more details on therm al perfor m ance )
Thermal Resistance Junction to Leads, θjl . . . . . . . . 15°C/W
Thermal Resistance Junction to Ambient, θja . . . 30-40°C/W
Note: The above numbers for θjl are maximums for the limiti ng thermal resist anc e of the packa ge in a standa rd moun ting con­figuration . The thermal perfor ma nce of t he dev ice/ pc- boar d sy stem . All of the above numbers assume no ambient airflow.
θ
ja numbers are meant to be guideline s for the
CONNECTION DIAG RAM
PLCC - 28 (Top View) QP Package
PACKAGE PIN FUNCTION
FUNCTION PIN
Inhibit 1 O/C Force 2 O/C Sen se 3 Range 4 C/S(+) 5 Comp Adj 6 O/C Ind 7
IN(+) 8
A
IN(-) 9
A V
C(+) Supply 10
A Output 11 Pwr Gnd 12 Pwr Gnd 13 Pwr Gnd 14 Pwr Gnd 15 Pwr Gnd 16 Pwr Gnd 17 Pwr Gnd 18 B Output 19
IN(+) 20
V
IN(-) 21
B B
IN(+) 22
REF Input 23 C/S(+) 24 C/S Out 25 IDIF Out 26 IDIF REF 27 Ground 28
ELECTRICAL CHARACTERIST ICS :
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
Input S u p pl y
V
IN (+)Supply Cur rent 12 16 mA
VC(+) Supply Current IOUT = OA 1.2 2.0 mA Total Supply Current Supplies = 5V,I
Supplies = 12V,I
V
IN(+) UVLO Threshold low to high 2.6 2.8 V
UVLO Threshold Hysterisis 300 mV
Over-Cur ren t (O/C) Comp ara tor
Input Bias Curr ent V input = 0.8V -1.0 -.01 µA Thresholds low to high 0.97 1.0 1.03 V Threshold Hys terisis 85 100 115 mV O/C IND Vs at I O/C IND Leakage V
OUT = 5mA, V input low 0.2 0.45 V
OUT = 20V 5.0 µA
Power Amplifiers A and B
Input Off set Voltage A Amplifier, V
B Amplifier, V Input Bias Current V CMRR V
CM = 6V -500 -50 µΑ CM = 0.5 to 13V, Supplies = 15V 70 90 dB
PSRR VIN(+) = 4 to 15V, VCM = 1.5V 70 90 dB Large Signal Volta ge G ain Supplies = 12V, V
to V
OUT = 10.5V, IOUT = -300mA 3.0 15.0 V/mV
OUT = OA 12 16 mA
OUT = OA 13 18 mA
CM = 6V 4.0 mV CM = 6V 12.0 mV
OUT = 1V, IOUT = 3 00mA
2
Page 3
UC3178
ELECTRICAL CHARACTERISTICS (cont.):
Unless otherwise stat ed spe cifica tion s hold for TA = 0°C to 70°C , VC(+) = VIN(+) = 12V, REF Input = V
IN(+)/2, O/C In put & Inhibit Input = 0V.
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
Power Amplifiers A & B (cont.)
Gain Bandwit h Prod uct A Amplifier 2.0 MHz
B Amplifier 1.0 MHz Slew Rate 1.0 V/µs High-Side Current Limit 0.45 0.65 A Output Saturation Voltage High-Side, I
High-Side, I
OUT = -100mA 0.75 V OUT = -300mA 0.85 V
High-Side, IOUT = -450mA 0.9 V
High-Side Diode, Vf I
Low-Side, I
Low-Side, I
Low-Side, I
Total Vsat, I
Total Vsat, I
Total Vsat, I
D = 450mA 1.30 V
OUT = 100mA 0.2 V OUT = 300mA 0.25 V OUT = 450mA 0.30 V
OUT = 100mA 0.95 1.2 V OUT = 300mA 1.05 1.4 V OUT = 450mA 1.25 1.6 V
Current Sense Amplifier
Input Offset Voltage V
CM = 6V, Low range mode 2.0 mV
High range mode 4.0 mV Input Offset Change V with Common Mode I npu t V Voltage Gain V
Saturation Voltage Low-Side, I
CM = -1V to 13V, Supplies = 12V, Low Range Mode 2000 µV/V CM = -1V to 13V, Supplies = 12V, High Range Mode 4000 µV/V DIFF = +1.0 to -1.0V, Vcm = 6V, High Range Mode 0 .485 0.50 0.515 V/V
V
DIFF = +1.0 to -1.0V, Vcm = 6V, Low Range M ode 1.95 2.0 2.05 V/ V
OUT = 1mA 0.1 0.3 V
High-Side, IOUT = -1mA, Referenced to = VIN(+) 0.1 0.3 V Input Bias Cu rrent at Ref. Input (REF Input - C/S(+))/48kohms, Tj = 25°C 152127µA/V
Load Curre nt Sen se and Re ctif icati on
Sense Buff er Off set Voltage REF I nput to IDIF REF, I Sense Buff er CMR R I IDIF REF to IDIF Out Cur ren t IDIF = Ratio IDIF = IDIF Out Supply Sen sitivit y IDIF Out = IDIF Out Commo n Mode Sens itivity IOUT =
±1mA, REF Input = 2V to 10V
OUT =
± 100
µA, IDIF Out = 1V 0.95 1.0 1.05 A/A
±1mA, IDIF Out = 1V
± 1mA, V
IN
(+)
±1mA, REF Input = 2V to10V, IDIF Out = 1V
±
OUT =
1mA 10 mV
70 90 dB
0.94 1.0 1.06 A/A
= 4V to 15V,REF Input = 2V
1.0 5.0 µA/V
(delta IDIF Out/de lta REF Inpu t) 1.0 5.0 µA/V
Auxi li ary Function s
Inhibit Input Threshold 0.6 1.1 1.7 V Inhibit Input Current Inhibit Input = 1.7V -1.0 -0.5 µA O/C Force Input Threshold 0.6 1.1 1.7 V O/C Force Input Current O/C Force Input = 1.7V 50 100 µA Range Input Threshold 0.6 1.1 1.7 V Range Inpu t Current Range Input = 1.7V 50 100 µA COMP ADJ Pin Satura tion Range Input = 0V, Pin Current = Voltage to A
OUT 0.02 0.1 V
±500µA, Referenced
COMP ADJ Leakage Curr ent Range Input = 1.7V, Supplies = 12V
AOUT
-VComp Adj = ±6V 5.0 µA
Total Supply Curren t When Inh ibited V
IN(+) and VC(+) currents 1.0 1.5 mA
Thermal Shutdown Tempe ratur e 165 °C
3
Page 4
UC3178
PIN DESCRIPTIONS:
A & B OUT: Outputs for the A & B power amplifiers,
providing differential drive to the load during normal op­eration. During a UVLO, Inhibit, or O/C condition both of these outputs will be in a high, source only state. High­side diodes are i ncluded to ca tch inductive load currents flowing into these pins, inductive kicks on the low-side are caught by the high-side output transistors.
A
IN(+): Non-inverting input to the A amp lifier. Normally tied
to the REF In pu t wh en the cu rr ent sen se am plif ier is used.
A
IN(-): Inverting input to the A amplifier. Used as the sum-
ming node to close the loop on the overall power amplifier.
B
IN(+): Non-inverting input to the B amplifier. This pin nor-
mally sets the reference point for the differential voltage swing at the load.
B
IN(-): Inverting input to the B amplifier. Used to program
the gain of the B amplifier. COMP ADJ: The compensation adjust pin allows the user
to provide an auxiliary compensation network f or t h e A am ­plifier that is only active when the current sense amplifier is in the low range. With this option, the user can control the change in bandwidth that would otherwise result from the gain change in the feedback loop.
C/S(+): The non-inv erting input to the current sense ampli­fier is typically tied to the load side of the series current sense resistor. This pin can be pulled below ground during an abrupt load current change with an inductive load. Proper operation of the current sense amplifier will result if this pin does not go below ground by an amount greater than:
C/S(-): The inverting input to the current sense amplifier is typically tied to the connection between the B amplifier output and the current sense resistor that is in series with the load.
C/S Output: The output of the current sense amplifier has a 1.5mA current source pull-up and an active NPN pull­down. The output will pu ll t o w ithin 0.3V of either rail with a load current of less than 1mA.
GND: Reference point for the internal reference, O/C comparator, and other low-level circuitry.
IDIF OUT: Current source output pin. The value of the out­put current is nominally equal to the magnitude of the current through the IDIF REF pin.
(REF In put / 2 ) - 0. 3 V.
IDIF REF: Output of the IDIF sense buffer. Voltage on this pin will track the applied voltage on the REF Input pin. Current through this pin is full wave rectified and appears as a current sourced from the IDIF OUT pin.
Inhibit : A high impe dance l ogic i nput that disabl es the A and B power amplifiers, the IDIF sense buffer, and the Current Sense amplifier. This input has an internal pull-up that will inhibit the device if the input is left open.
O/C Force: Logic input that forces the O/C condition. O/C IND: Open collector ouput that indicates, with an ac-
tive low state, an O/C condition. O/C Sense: Input to the Over Current Comparator. When
this input is above its 1V threshold the low-side devices of both the A & B power amplifiers will be disabled forcing a high, source only , state at both outputs.
PWR GND: Current return for all high level circuitry, this pin should be connected to the same potential as GND.
Range: When this pin is open or at a logic low potential, the current sense ampli fier will be in its low range mode. In this mode the vo ltage gain o f the amplifier will be 2. If this pin is brough t to a logic high, the gain of the current sense amplifier will change into its high range value of
0.5. This factor of four change in gain will vary the overall transconductance of the power amplifier by the same ra­tio, with the transconductance being the highest in the high mode. This feature al lows improved dynamic range of load curren t control for a give n con trol input range and resolution.
REF Input: Sets the Reference level at the C/S Output, and is normally tied to the system reference level for in­puts to the power amplifier.
V
IN(+): Provides bias supply to the device. The High-Side
drive to the power stages on both the A and B amplifiers is referenced to this pin. The High-side saturation volt­ages, and UVLO are specified and measured with respect to this supply pin.
V
C(+): Thi s supply pin is the high current supply to the
collectors o f the high-side NPN output devices on the A and B ampl ifiers. This supply should be powered when­ever the A or B amplifiers are to be activated. This pin can operate approximately 400mV below the V
IN(+) supply
without affecting the voltage available to the load.
4
Page 5
UC3178
TYPICAL APPLICATION
Power amplifier transconductance
Go
=
Il
Vs
=
RA
RB
Peak commanded load current Il
UNITRODE INTEGRATED CIRCUITS 7 CONTINENTAL BLVD.MERRIMACK, NH 03054 TEL (603) 424-2410 FAX (603) 424-34 60
MAX
=
V
o/c
RS
AV
CS
AV
1
RD
CS
RS
RE
where:
Il
is the load current
Vs
is the input command voltage
AV
is the current sense amplifier gain
CS
= 2.0 in low range mode = 0.5 in high range mode
V
is the 1.0V over-current comparator thresh old
O/C
5
UDG-92009
Page 6
IMPORTANT NOTICE
T exas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability.
TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent TI deems necessary to support this warranty . Specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements.
CERTAIN APPLICA TIONS USING SEMICONDUCT OR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICA TIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERST OOD TO BE FULLY AT THE CUSTOMER’S RISK.
In order to minimize risks associated with the customer’s applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards.
TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right of TI covering or relating to any combination, machine, or process in which such semiconductor products or services might be or are used. TI’s publication of information regarding any third party’s products or services does not constitute TI’s approval, warranty or endorsement thereof.
Copyright 1999, Texas Instruments Incorporated
Loading...