a1614AT - Alpha Microelectronics GmbH

June 1999 alpha mi croelectronics gm bh Page 1/12

Description

The ú1614, combined with an external NMOS, is

used as a low loss driver for coils, relays or

magnets.

You can choose between a current controlled and

a voltage controlled PWM to drive the load.

An external resistor is used for current controlled

regulation.

Two additional external resistors are necessary for

the voltage-controlled PWM mode.

The hold current, the overexcitation coil current and

the overexcitation time are adjusted separated in

both cases.

The bootstrap output, with square pulses, can be

used for further applications.

The chip overtemperature protection is adjusted

from 80 to 150 °C with an external resistor.

Chip overtemperature, undervoltage errors and

relay status are indicated on input IN.

Features

q Voltage supply 8 to 45 VDC

q 5-V and 12-V reference voltage output

q Quiescent current 2 mA

q Output current up to 200 mA

q Current or voltage controlled regulation of the

coil current

q Adjustable oscillator frequency 50 Hz to 5 kHz

q Adjustable hold and overexcitation coil current

q Adjustable overexcitation time

q Bootstrap output up to 2 mA

q Undervoltage lockout and power-on reset

q Overvoltage protection for the external NMOS

q Protection against reversed battery and EMC

q Adjustable chip overtemperature protection

q Temperature range -40°C to +150°C

q Package SOP 18 ú1614AT

Die ú1614AX

Applications

q Current controlled driver for coils

q PWM driver for relays

Typical Application Coil driver using ú1614

COSC

CTO

RCH

RCO

RPT

RREF

CVDDC

RSEN

VDD

10n

output

Input

Mode B

Mode A

15K

30K

75K

18K

680n

220n

MODA

1614

INCH

CTO

VDDC

VDD

MODB

INCO

IRCR

INPT

OUT

OVP

BOUT

GND

SEN

COSC

5INST 9

VREF 100n

CVREF

Coil Driver IC

ú1614

Preliminary Data Sheet

Page 2/12 alpha mi croelectronics gm bh June 1999

Functional Block Diagram

Reference

Regulator

Logic

Internal

Current

Thermal

Shutdown

Undervoltage

Lockout

vU=20 2

Prestababilization

7V for Reference Prestababilization

12V for Driver

Bootstrap

Mode-Logic

Frequency

Control

tOE- Trigger R

a nd L ogic S

Error-Logic

Divider

1:4

Latch

Turn on / off

Logic

VDD

1716

VDDC

CVDDC

INCH

INCO

MODB

MODA

Input

Mode A

Mode B

ì1614

S4 S5 S6

Driver

DZ1

48V

DZ3

16V

DZ2

VPSR VPSD

Oscillator

11281110

SEN

50µ 50µ

INPT

COSC

CCO

RCH RCO RPT RREF

OSCCTOIRCR GND

30k

1,5µ



50µ

2,5V

200k

OUT

BOUT

OVP

RSENSE

VREF

CREF

INST

Relay

St atus Input

500K

June 1999 alpha mi croelectronics gm bh Page 3/12

Pin Definition

Pin Symbol Designation

1 SEN Current Sense Input

2 OVP Overvoltage Protection Output for external MOSFET

3 OUT Output

4 BOUT Bootstrap Output

5 INST Input for Status Relay

6 MODA Mode A Input

7 MODB Mode B Input

8 CTO Capacitor for Overexcitation Time

9 VREF Reference Voltage Output

10 INPT Resistor for Overtemperature Protection

11 IRCR Resistor for Current Reference

12 OSC Capacitor for Oscillator Frequency

13 INCH Resistor for Hold Current

14 INCO Resistor for Overexcitation Current

15 IN Input

16 VDDC Block Capacitor

17 VDD Supply Voltage

18 GND GND

The location of pins can be changed during the development.

General function and description

The ì1614 combined with an external N-channel power MOSFET serves for the low loss control of

electrical magnetic actuators like relays or magnets and similar kinds of coils. It is especially suitable in

automotive applications. The ì1614 can operate either in current-mode or voltage-mode control to

regulate the load current.

Current-mode control

The oscillator sets a latch which turns the external low-s ide transistor on. The load induc tance is charged

from the s upply voltage. The load current incr eases until the voltage drop over the sens e res istor reaches

the external programmed value. Then the comparator resets the latch witch turns the external transistor

off . Now the load current f lows through the fr ee-wheeling diode and r em ains nearly constant until the nex t

oscillator set impulse. By changing the oscillator frequency with an external capacitor the free-wheeling

duration can be varied.

Voltage-mode control

In case of voltage-mode control the PWM ratio is controlled in a way that the energy in the inductance

remains nearly constant over a defined supply voltage range.

For an optimal adaptation to the load inductance both current levels (hold / overexcitation) and the

overexcitation time can be adjusted externally and independently.

The ÷1614 has various safety functions and diagnostic functions such as overvoltage protection,

undervoltage lockout, detection of broken wire or short circuit. Fault events are indicated on IN.

Page 4/12 alpha mi croelectronics gm bh June 1999

PIN function and description

VDD

The ú1614 is designed for a supply voltage of VDD = 8 ... 45V. The IC includes a diode in the VDD line

(VFD ≈ 0.6V, VBR ≤ 400V), saving it against reversed polarity of the supply voltage. The internal diode and

the pass transistor of the internal 12-V preregulator are designed for a maximum peak current of 75mA. If

necessary the peak current has to be limited by an external resistor in the power supply line.

The undervoltage detection disables at VDD ≈ 7.5V the push-pull output stage and the bootstrap driver.

This error state is reported on the IN input with low level. Therefore is the error state in case of mode 3

with a permanent low-level input signal (turn-on) not readable.

VDDC

The VDDC voltage (VDD-0.6V) supplies power to the 5-V reference and 12-V preregulator providing the

output driver and the bootstrap driver. Bypass this pin with a capacitor.

VREF

The internal 5-V reference voltage must be bypassed with a capacitor of 100nF. It supplies power the

internal logic and the power-on-reset circuitry (turn-on threshold at VREF ≈ 4V). The VREF pin can

provide an additional current up to 1mA to an external load. The output signals of the undervoltage

detector and the power-on-reset circuitry are logically AND connected.

OUT

The output of the push-pull driver charges / discharges the external NMOS Transistor with up to 200mA.

The maximum output voltage of the driver is 12V.

OVP

The OVP input is internally connected through a series of zener diodes and forward biased diodes to the

OUT output. Thereby the external transistor is protected from overvoltages higher then 48V (see figure 1

and 2). If the current into the OVP input gets higher than 30µA, the overvoltage function will be enabled.

The internal sink transistor of the driver stage is turned off and the external transistor is turned on.

If an external MOSFET with a higher breakdown voltage is used, the overvoltage protection threshold can

be adjusted with an external zener diode.

BOUT

The bootstrap push-pull driver generates a square wave voltage (50% DC) with an amplitude of about 12V

and with the same frequency as the oscillator frequency.

An faster discharge of the inductance can be achieved with an additional circuitry including a voltage

multiplier and a NMOS transistor( see figure 5).

The bootstrap driver will controlled via the input IN. The bootstrap output shows low level in the turn-off

state and in the error state.

MODA an d MODB

Four input modes can be programmed according the following table. Open inputs will be detected as high

level.

Mode description MODA MODB

Mode 1 AC-input and external PWM-control open / VRef GND

Mode 2 AC-input and internal PWM-control GND GND

Mode 3 Low active DC input and internal PWM-control GND open / VRef

Mode 4 High active DC input and internal PWM-control open / VRef open / VRef

Besides the turn-on / turn-off function the IN input serves as a status output.

In case of an error event the input changes to low level (about 1V).

The high-impedance input has to be connected only to an open-collector stage or open-drain stage.

The high Schmitt trigger input stage detects input voltages higher than 3V as a high signal and input

voltages lower than 2.5V as a low signal. An open input is interpreted as a high signal. Short transient

impulses at the input are filtered by an internal RC filter with a 700-ns time constant. The maximum input

voltage is 80V. The input IN is protected against negative voltages up to -80V.

The input impedance can be lowered wi th a resistor between VDDC and IN.

The input frequency and oscillator frequency have to be in a defined ratio at the dynamic modes mode 1

and mode 2. An advantage of the dynamic input control is the self detection of broken wire or short circuit

on the input.

June 1999 alpha mi croelectronics gm bh Page 5/12

According to the four input modes (programmed at MODA, MODB) are the following variants for the input

control possible:

Mode 1 Dynamic input control (low active), with external PWM control

turn-on condition fIN > 0.6*fOSC

turn-off condition fIN < 0.4*fOSC

INCH, INCO, CTO = GND / low signal and SEN = open / VRef’

The output stage is directly controlled from the input signal. The switch-on delay and switch-

off delay are related to the phase position between input frequency and oscillator frequency

and may be (1 ... 2) *TPOSC.

The functions current-mode control, voltage-mode control, overexcitement, hold, and final-

position-contact detection are disabled in this mode.

Mode 2 Dynamic input control with internal PWM-control

turn-on condition fIN = 1*fOSC

turn-off condition fIN < 0.4*fOSC

retrigger condition fIN = 2**fOSC

In opposite to Mode 1 the input frequency does not serve for the direct control of the output

stage. Mode 1 results in a turn-on ( fIN = fOSC ) that is always combined with a switch-on

overexcitation. A change to the double input frequency (fIN = fOSC → fIN = 2*fOSC) causes a

renewed overexcitation (refresh, retriggering). Every further refresh needs such input

frequency change.

The switch-on delay and switch-off delay, the delay for the retriggering, and the delay for the

change back from double to simple input frequency are also directly depended on the phase

position between input frequency and oscillator frequency and can be (1 ... 2) *TPOSC.

After the turn-on at the input starts the current-controlled or voltage-controlled regulation.

Mode 3 Static input control (low active), with internal PWM control

turn-on condition high-low slope

turn-off condition VInput > 4V

retrigger condition high-low slope

The static input control performs only the turn-on function. The input controls the output

driver not direct. After turning on combined with overexcitation starts the current-controlled or

voltage-controlled regulation without any delay. A refresh (retriggering) can be initiated with a

short turn-on - turn-off sequence. The power supply voltage has to exist before the turn-on

condition, otherwise the switch-on overexcitation will not be executed.

After an undervoltage detection or chip overtemperature a high-low slope on the input has to

be generated to perform a switch-on overexcitation.

Mode 4 Static input control (high active), with internal PWM control

turn-on condition low-high slope

turn-off condition VInput < 2V

retrigger condition low-high slope

The mode 4 is the “inverse case” of mode 3. See mode 3.

OSC

The current source at the oscillator input provides a charge /discharge current of +/-50µA into the external

capacitor COSC and generates a triangle wave. The lower comparator threshold of the oscillator is 0.8V,

the upper comparator threshold is 4V. The triangle wave is used for the voltage-controlled regulation. It is

transformed into a square wave setting the latch for current controlled regulation.

The following divider stage divides the oscillator frequency by 4 for the analysis of the input frequency.

The ì1614 is intended to use in a frequency range of 50 Hz to 5kHz.

For the calculation of COSC is valid: COSC [nF] = 7710 / fOSC [Hz]

CTO

The capacitor CTO setting the overexcitation time TCTO up to 3s is connected to the CTO pin.

The charging current for the capacitor is about 1.4µA and the threshold is 4.5V. The value of the capacitor

is limited to 1µF. The maximum discharge time of the capacitor is 10ms. During the discharge time a

renewed overexcitation is not allowed.

For the calculation of CTO is valid: CTO [nF] ≈ 0.3*TCTO [ms]

Page 6/12 alpha mi croelectronics gm bh June 1999

INCO and INCH

External resistors at both inputs set the values of overexcitation current and hold current. Each internal

current source provides a current of 50µA.

Current-controlled regulation:

Both inputs are connected to GND with a resistor. The values of the resistors are the following if the

oscillator levels are 4V and 0.8V.

overexcitation mode: RCO = 4000mV / 50µA = 80kΩ

hold mode: RCH = 800mV / 50µA = 16kΩ

In case of current regulation both inputs can be also controlled by an external voltage (instead of a

resistor).

Supply-voltage controlled regulation:

Two external resistors between the inputs INCO, INCH and the VDDC pin set the desired supply-voltage

dependence for the overexcitation current and hold current (see fig. 2). In opposite to the current-mode

control the voltage on the input INCH is higher than the voltage on the input INCO, e.g.

maximum overexcitation (PWM = 99%): VINCO ≈ 830mV,

minimum hold (PWM = 1%): VINCH ≈ 3970mV

The target voltages VINCH and VINCO are compared with the comparator to the oscillator triangle wave.

The comparison causes the turn-on of the output stage at the rising oscillator voltage and the turn-off of

the output stage at the falling oscillator voltage.

In case of supply-voltage regulation current limitation and short circuit protection for the external transistor

has to be provided by an external circuitry.

SEN

Connecting a sense resistor to the sense input SEN sets the IC automatically in current-mode control (see

fig. 1). The minimum input voltage at the sense input is 40mV; the maximum input voltage is 200mV.

Voltage peaks higher then 3V are not allowed on the input SEN. The ratio of the overexcitation current to

hold current is limited to maximal 5 to 1.

The sense input voltage amplified with a gain of 20 is leaded to the PWM comparator K1. The amplifier

output voltages are the following:

Minimal actual voltage (hold): 40mV*20 = 800mV

Maximal actual voltage (overexcitation): 200mV*20 = 4000mV

The target voltage on the other input of the comparator will be formed on the inputs INCH (hold) and INCO

(overexcitation).

In case of an open sense input IC stays in the supply-voltage control. Changing between supply-voltage

controlled regulation and current regulation is not allowed.

IRCR

A resistor on this input sets the reference current for the internal IC biasing. The temperature independent

voltage on this pin is 1.5V. An external resistor of RCR = 30kΩ ± 1% provides a reference current of 50µA

(1.5V / 30kΩ). The temperature coefficient and the accuracy are directly dependent on the external

resistor.

June 1999 alpha mi croelectronics gm bh Page 7/12

INPT

The 50-µA current source on the input of the thermal shutdown generates a voltage drop over the

external resistor RPT. The thermal shutdown circuitry compares this voltage with the voltage of two forward

biased diodes (TC = -4mV/°C). By varying the value of RPT any desired shutdown temperature is

programmable. The thermal protection has a temperature hysteresis of 6°C.

If the thermal shutdown is active all IC functions are turned off. This state is reported to the output OST.

After thermal shutdown releases, all IC functions starts in the same way as the turn-on over the supply

voltage.

In case of mode 1, mode 2 or mode 4 overexcitation is automatically performed, also in the present of an

input signal during temperature shutdown.

In case of mode 3 overexcitation has to be external triggered (with a short turn-off-turn-on input sequence)

after thermal shutdown releases. Without these retriggering the IC turns on only in the hold mode. The

error state in case of mode 3 with a permanent low-level input signal (turn-on) is not readable.

If the input INPT is connected to GND, the thermal shutdown is disabled.

An open input turns off the IC immediately. The input INPT can also be controlled with a voltage.

For the calculation of RPT is valid:

RPT [nF] = 22kΩ - 0.076kΩ / K*(TOff - 60°C)

INST

These input is intended for the use of relays with a separate final-position contact.

The ì1614 automatically starts a single overexcitation in case of a forbidden release of the relay

armature (see fig. 3). If the relay armature does not pull until the end of the overexcitation time because of

a defect in the winding or other mechanical errors, all functions of the IC are switched off. The error state

is signaled with low level (≈ 1V) on the status output.

A renewed start of the IC is only possible after a power-on reset caused by a switch-off / switch-on of the

supply voltage.

The error state in case of mode 3 with a permanent low-level input signal (turn-on) is not readable.

Page 8/12 alpha mi croelectronics gm bh June 1999

Absolute Maximum Ratings

at Tamb = -40°C ... +150°C

Symbol Parameter Min Max Unit

VDD Supply Voltage -300 100 V

-IBOUT Output Current BOUT -5 5 mA

IOVP Output Current OVP, t < 10µs 0 40 mA

IOUTp Output Current OUT, t < 200µs -200 200 mA

IOUT Output Current OUT -10 10 mA

-IVDDC Output Current VDDC 0 20 mA

IIN Input Current IN 0 20 mA

VIN Input Voltage IN 45 VDDC V

IREF Input Current REF -100 0 µA

VMODx Input Voltage MODA, MODB 0 5 V

VCOSC Input Voltage COSC 0 5 V

VCTO Input Voltage CTO 0 5 V

VSEN Input Voltage SEN 0 5 V

VINxx Input Voltage INPT, INCO, INCH, INST, IRCR 0 5 V

CVDDC Block Capacitor CVDDC dependent on VDD, VDD = 15V

VDD = 45V 1

0.22 µF

µF

RREF Resisto r RREF 29.4 30.6 kW

TCREF Temperature Coefficient RREF 50 ppm

TjJunction Temperature - 175 °C

Tstg Storage Temperature Range -55 150 °C

Rthja Thermal Resistance SOP18 95 K/W

June 1999 alpha mi croelectronics gm bh Page 9/12

Electrical Characteristics

Operational Range

Symbol Parameter Min Max Unit

VDD Supply Voltage 8 45 V

VSEN Input Voltage SEN 40 200 mV

ICO / ICH Ratio - Overexcitation Current / Hold Current 5

fOSC Oscillator Frequency ( Bootstrap Frequency ) 50 5000 Hz

TaAmbient Temperature Range -40 150 °C

DC Characteristics

at Ta = -40°C ... 150°C, VDD = 15V, RREF = 30kW; unless otherwise specified

Symbol Parameter Conditions Min Typ Max Unit

IDD Current Consumption OUT, BOUT = open,

IN = turn ON 23mA

VDD LON

VDD LOF

Undervoltage Lockout Turn on

Turn off 7.5

7.25 V

VREF LON

VREF LOF

Power on Reset Turn on

Turn off 4.0

4.0 V

/ VREF / Reference Voltage -IREF = 100µA 4.75 5.0 5.25 V

aSEN Gain OVSEN Ta = 25°C

VSENSE = 100mV 19 20 21

IINCO Input Current INCO VINCO = 3V -50 µA

IINxx Input Current INCH, INPT VIN = 800mV -50 µA

Ta OFF Thermal turn OFF RTH = 15kW140 °C

Ta ON Thermal turn ON RTH = 15kW132 °C

AC Characteristics

at Ta = 25°C, VDD = 15V, RREF = 30kW; unless otherwise specified

Symbol Parameter Conditions Min Typ Max Unit

fOSC Oscillator Frequency COSC = 10nF 740 770 800 Hz

tOOverexcitation Time CtO = 33nF 100 110 120 ms

Page 10/12 alpha microelec t roni cs gm bh June 1999

Further applications

Examples for further applications of the ú1614 are:

• Current-controlled regulation with overvoltage protection for M1 (see fig. 1)

• Supply-voltage controlled regulation with overvoltage protection for M1 (see fig. 2)

• Current-controlled regulation with final-position contact function and overvoltage protection for M1 (see

fig 3)

• Input-controlled PWM (see fig. 4)

• Current-controlled regulation with faster discharge of the inductance (see fig. 5)

Fig 1: Current-c ontrolled regulati on with overvol tage protecti on for M1

Fig. 2: S uppl y-vol tage controll ed regul at i on with overvol tage protect i on f or M1

June 1999 alpha mi croelectronics gm bh Page 11/12

Fig. 3: Current -controlled regulation with final-position c ont act func tion and overvoltage protection for M1

Fig. 4: I nput-controll ed P WM regulation

Fig. 5: Current -controlled regulation with fast er di scharge of t he i nductance

Page 12/12 alpha microelec t roni cs gm bh June 1999

Package 18-pin Plastic SOP

11118765432

1118 17 16 15 14 13 12

11.57



0.1

7.40



0.2

0.42



0.07

10.16

1.27

2.65 max.2.4 m ax.

>0.3

10° m ax. 0.27

0.15

10.4



0.2

7.4



0.2

SOP 18

Note

It is not given warranty that the declared circ uits, devices , facilities , components, assembly groups or t reat ments included herein

are free from legal clai ms of third parties.

The declared data are onl y a description of product. They are not guaranteed properties as defined by law. The examples are gi ven

without obligation and cannot given rise t o any liability.

Reprinting t hi s data sheet - or part s of it - is only allowed with a licens e of the publis her.

alpha mi croelectronics gm bh reserves the right to m ak e changes on this specificati on without notice at any time.

alpha microelectronics gmbh

Im Technologiepark 1 Tel ++49-335-557 1750

15236 Frankfurt (Oder) Fax ++49-335-557 1759

Germany Internet http://www.alpha-microelectronics.de

email alpha@alpha-microelectronics.de

1614DSHa.doc