Microchip Technology TC170CPE, TC170COE Datasheet

TC170

E

SHDN

SO

/

SE

SE

N

R

N

.

6

5

0COE

/

SE

SE

N

R

N

)

)

CMOS Current Mode PWM Controller

Features

• Low Supply Current With CMOS Technology:

3.8mA Max

• Internal Reference: 5.1V

• Fast Rise/Fall Times(C

= 1000pF): 50nsec

L

• Dual Push-Pull Outputs

•Direct-PowerMOSFETDrive

• High Totem-Pole Output Drive: 300mA

• Differential Current-Sense Amplifier

• Programmable Current Limit

• Soft-Start Operation

• Double-Pulse Suppression

• Undervoltage Lockout

• Wide Supply Voltage Operation: 8V to 16V

• High Frequency Operation: 200kHz

• Available with Low OFF StateOutputs

• Low Power, Pin-Compatible Replacement for

UC3846

Applications

• Switching Power Supplies

• DC/DC Converters

• Motor Control

General Description

The TC170 offers maximum supply current of 3.8mA.
Bipolar current-mode control integrated circuits require
five times more operating current.

The dual t otem-pole CMOS outputs drive power
MOSFETs or bipolar transistors. The 50nsec typical
output rise and fall times (1000pF capacitive loads)
minimize MOSFET power dissipation. Output peak
current is 300mA.

The TC170 contains a full array of system-protection
circuits (see Features Section).

Current-mode control lets users parallel power supply
modules.Two or more TC170 controllers can be slaved
together for parallel operation. Ci rcuits can operate
from a master TC170 internal oscillator or an external
system oscillator.

The TC170 operates from an 8V to 16V power supply.
An internal 2%, 5.1V r eference minimizes external
component count. The TC170 is pin compatible with
the Unitrode UC1846/UC2846/UC3846 bipolar
controller.

Other advantages inherent in current-mode control
includesuperior line and load regulation and automatic
symmetry correction in push-pull converters.

Device Selection Table

Part Number Package Temp. Range

TC170COE 16-Pin SOIC (Wide) 0°C to +70°C
TC170CPE 16-Pin PDIP (Narrow) 0°C to +70°C

Package Type

16-Pin PDIP (Narrow

FT START

V

REF

– I

EN

+ I

EN

+ ERROR AMP I

– ERROR AMP I

MPT

NOTE: Outputs LOW in "OFF" state

TC170CP

1

1

FT START

V

REF

– I

EN

+ I

EN

+ ERROR AMP I

– ERROR AMP I

MPT

16-Pin SOIC (Wide

16

15

14

TC17

13

12

10

11

9

SHDN

V

IN

OUTPUT B

V

DD

GND

OUTPUT A

SYNC

R

O



2002 Microchip TechnologyInc. DS21395B-page 1

TC170

Functional Block Diagram

15

V

IN

9

R

Sync

(–) Current

Sense Input

(+) Current

Sense Input

Comp

(+) Error

Amp Input

(–) Error

Amp Input

O

C

O

10

8

3

4

7

5

6

Oscillator

–

+

100µA

+

–

Error
Amplifier

x 3.15 Current
Amplifier

–

0.75V

V

DD

Q3

Lock-up
Amplifier

+

+

–

Limit Buffer
Amplifier

350mV

PWM
Comparator

+

–

Q4

–

+

Positive
Feedback

5.1-Volt

Reference

Undervoltage

Lockout

S

S

R

Q

PWM Latch

Q1

V

REF

Q2

3.5kΩ

2

13

11

14

12

V

DD

Output

A ( )

Output
B ( )

Ground

DQ
C

Q

Shutdown

Comparator

+

–

6kΩ

TC170

350
mV

1

Current Limit/
Soft-Start Adjust

16

Shutdown

NOTE: Outputs low in OFF state.

DS21395B-page 2



2002 Microchip TechnologyInc.

TC170

1.0 ELECTRICAL
CHARACTERISTICS

*Stresses above those listed under "Absolute Maximum
Ratings" may cause permanent damage to the device. These
are stress ratings only and functional operation of the device
at these or any other conditions above those indicated in the

Absolute Maximum Ratings*

Supply Voltage.......................................................18V

Output Voltage ........................................... V

Analog Inputs ..................................-0.3V to V

DD

S

or 18V
+0.3V

operation sections of the specifications is not implied.
Exposure to Absolute Maximum Rating conditions for
extended periods may affectdevice reliability.

Package Thermal Resistance:

SOIC (Wide) θ
SOIC (Wide) θ
PDIP (Narrow) θ
PDIP (Narrow) θ

.....................................105°C/W

JA

.......................................23°C/W

JC

....................................95°C/W

JA

....................................55°C/W

JC

Operating Temperature Range ...............0°C to +70°C

StorageTemperature Range..............-65°C to +150°C

TC170 ELECTRICAL SPECIFICATIONS

Electrical Characteristics: VIN=16V,RO=24kΩ,CO= 1nF, TA= 25°C, unless otherwise noted.

Symbol Parameter Min Typ Max Units Test Conditions

Reference Voltage

V

REF

Reference Voltage 5 5.1 5.3 V I
Line Regulation 5 15 mV V
Load Regulation 13 20 mV I

V

RTC

Temperature Coefficient 0.4 0.5 mV/°C Overoperating temperature range.

Oscillator

F Oscillator Frequency 35 42 46 kHz
VC
TC

Voltage Stability 1.1 1.5 %/V VIN=8Vto16V

OSC

T emperature Stability 5 10 % Over operating temperature range.

OSC

Error Amplifier

V

OS

I

B

V

CMRR

A

VOL

Input Offset Voltage ±30 mV
Input Bias Current ±1 nA
Common-Mode Input Voltage 0 VDD–2V V VIN=8Vto16V

Open-Loop Voltage Gain 70 dB V
BW Unity Gain Bandwidth 1.2 MHz
CMRR Common-Mode RejectionRatio 60 dB V
PSRR Power Supply Rejection Ratio 60 dB V

Current Sense Amplifier

A
V
V

IAMP
DM
CM

Amplifier Gain 3 3.15 3.3 V/V Pin 3 = 0V to 1.1V

MaximumDifferential Input Signal ≤ 1.1 V V

Common-Mode Input Voltage 0 VDD–3V V

Current LimitAdjust

V

OS

I

B

Current Limit Offset Voltage 0.5 1 V

Input Bias Current 1 nA

Shutdown Terminal

V

TH

V

IN

I

L

I

L

Threshold Voltage 0.3 0.35 0.4 V

Input Voltage Range 0 V

DD

MinimumLatching Currentat Pin 1 125 µA

MaximumNonlatchingCurrent at Pin 1 50 µA

V

=1mA

OUT

=8Vto16V

IN

= 1mA to 10mA

OUT

=1Vto6V

OUT

=0Vto14V

CMV

=8Vto16V

IN

PIN4–VPIN3



2002 Microchip TechnologyInc. DS21395B-page 3

TC170

TC170 ELECTRICAL SPECIFICATIONS (CONTINUED)

Electrical Characteristics: VIN=16V,RO=24kΩ,CO= 1nF,TA= 25°C, unless otherwise noted.

Symbol Parameter Min Typ Max Units Test Conditions

Output Stage

V

DD

V

OL

V

OL

V

OH

V

OL

t

R

t

F

OutputVoltage VIN–0.5 V
OutputLow Level 0. 4 V I
OutputLow Level 2 V I
OutputHighLevel VDD–1V V I
OutputHighLevel VDD–4V V I
OutputRiseTime 50 150 nsec CL= 1000pF
OutputFallTime 50 150 nsec CL= 1000pF

Undervoltage Lockout

Start-Up 7.15 7.7 8.25 V Threshold
Threshold Hysteresis 0.5 0.75 1 V

Supply

I

S

StandbySupplyCurrent 2.7 3.8 mA

VIN+0.5 V Pin13

IN

=20mA

SINK

= 100mA

SINK
SOURCE
SOURCE

=20mA
=100mA

DS21395B-page 4



2002 Microchip TechnologyInc.

TC170

2.0 PIN DESCRIPTIONS

ThedescriptionsofthepinsarelistedinTable2-1.

TABLE 2-1: PIN FUNCTION TABLE

Pin No.

(16-Pin PDIP,

SOIC)

1SOFTSTART/I

2V
3-I

4+I

5 +ERROR AMP IN +Error Amp In. Non-inverting input for output voltage regulation.
6 -ERROR AMP IN -Error Amp In. Inverting input of the amplifier for the reference voltage.
7 CMPTR For compensation of the feedback loop response.
8C

9R

10 SYNC ForPWM controlleroscillator synchronizationof two or morecontrollers.Or as a clockinput to

11 OUTPUT A A output drive of phase A from push pulltransistors.
12 GND Ground return for all input and output pins.
13 V
14 OUTPUT B Output of phase B from push pull transistors.
15 V
16 SHDN Input pin to disable both output drivesto 0V OFF.

Symbol Description

Soft Start Adjust/Current Limit. For setting the peak current threshold of sense inputs (pins 3

LIM

and 4). Second function of this pin is Soft-Start Adjust.

OUT Reference supply outputof 5.1 volts.It can supply a minimum of 10mA.

REF

IN -CurrentSenseInput. Invertinginputforsensing peak current of the pass transistor through

SENSE

SENSE

O

O

DD

IN

seriessensecurrent monitor resistor.

IN +Current Sense Input. Non-inverting input used in conjunction with pin 3. This senses the

positive end of current monitor resistor.

Timing capacitor (CO) input to set oscillator frequency in conjunction with pin 9, RO,resistor
input. Second function is for setting crossover dead time of pin 11and 14 outputs.

Timing resistor (RO) input to set oscillator frequency by setting constant current charge rate to
charge capacitor C

sync oscillator from externalsignal.

Supplies power to operate the output drivers only.

Voltage bias supply for all TC170 circuits except the output transistors.

.

O



2002 Microchip TechnologyInc. DS21395B-page 5