June 1999 alpha mi croelectronics gm bh Page 1/12
Description
The ú1624 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 chip overtemperature protection is adjusted
from 80 to 150°C with an external resistor.
Chip overtemperature, undervoltage errors and
relay status are indicated on a status output.
Features
q Voltage supply 18 to 400VDC
q 5-V and 12-V reference voltage output
q Quiescent current 2 mA
q Output current up to 200mA
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 Undervoltage lockout and power-on reset
q Protection against EMC
q Adjustable chip overtemperature protection
q Temperature range -25°C to +85°C
q Package SOP 18 ú1624ET
Die ú1624EX
Applications
q Current controlled driver for coils
q PWM driver for relays
Typical Application Coil driver using ú1624
10
11
3
13
8
7
6
14
18
12
1
16
15
4
2
17
COSC
CTO
RCH
RCO
RPT
RREF 10n
Input
Mode B
Mode A
15K
30K
75K
18K
680n
IN
MODA
ú
1624
INCH
CTO
VDDC
VDD
MODB
INCO
IRCR
INPT
OUT2
OUT1
OST
GND
SEN
OSC
5INST 9
VREF 100n
CVREF
CVDDC
220n
RSEN
DL
VDD
RSEXT
Coil Driver IC
ú1624
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
1
2
3
4
4
3
3
4
vU=20 2
Status
Mode-Logic
Frequency
Control
tOE- Trigger R
and Logic S
Error-Logic
Divider
1:4
S
R
Q
Latch
Turn on / off
Logic
VDD
17
14
6
7
13
3
IN
INCH
INCO
MODB
MODA
Input
Mode A
Mode B
ì
1624
S1
S2
S3
S4 S5 S6
K1
Driver
K2
16V
DZ2
5
6
Oscillator
1281110
SEN
50µ 50µ
INPT
COSC
CCO
RCH RCO RPT RREF
COSCCTOIRCR
30k
1.5µ
50µ
50µ
3V
2.5V
M3
VREF
9
CREF
INST
Relay
Status Input 5
RSEXT
9V
RV
DZ3
M2
200k
Internal
Current
14V
2
VDDC
CVDDC
M4
VDD
D
18
GND
4
15
16
OUT2
OST
RSEN
Status
Output
500K
500K
500K
500K
OUT1
1
June 1999 alpha mi croelectronics gm bh Page 3/12
Pin Definition
Pin Symbol Designation
1 SEN Current Sense Input
2 VDDC Block Capacitor
3 INCO Resistor for Overexcitation Current
4 OST Output for Status
5 INST Input for Relay Status
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 Reference Current
12 OSC Capacitor for Oscillator Frequency
13 INCH Resistor for Hold Current
14 IN Input
15 OUT1 Output 1
16 OUT2 Output 2
17 VDD Supply Voltage
18 GND GND
The location of pins can be changed during the development of the layout.
General function and description
The ì1624 serves for the low loss control of electrical magnetic actuators like relays or magnets and
similar kinds of coils. It is especially suitable for the 240-V mains. The ì1624 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 internal low-side switch transistor on. The load inductance is
charged f rom the supply voltage. The load curr ent increas es until the voltage drop over the sens e r esistor
reaches the external programmed value. Then the comparator resets the latch witch turns the switch
transistor off. Now the load current flows through the free-wheeling diode and remains nearly constant
until the next 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 ÷1624 has various safety functions and diagnostic functions such as overvoltage protection,
undervoltage lockout, detection of broken wire or short circuit, and a status output.
Page 4/12 alpha mi croelectronics gm bh June 1999
PIN function and description
VDD
The ú1624 is designed for a supply voltage range of VDD = 18 ... 400V. The IC is not protected against
reversed polarity of the supply voltage. The internal power supply is 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.
For the calculation of RVDD is valid: RVDD = (VDD-150V) / 75mA
VDDC
The internal preregulated voltage of about 12V is connected to the Pin VDDC and must be bypassed with
a capacitor. The voltage on VDDC supplies power to the gate driver of the switch transistor and the
internal 5-V reference. Undervoltage detection is performed on VDDC.
If the VDDC becomes higher than 6.9V the IC will be enabled (with RVDD = 0 is VDD ≈ 9.5V).
If the VDDC voltage is lower than 6.7V all functions of the IC are disabled, the output stage is turned off,
and the status output indicates low level (with RVDD = 0 is VDD = 8.7V).
The VDDC pin can provide an additional current up to 1mA to an external load. In that case the IC power
dissipation at higher supply voltages has be taken into consideration.
VREF
The internal 5-V reference voltage is supplied from VDDC and has to be decoupled with a capacitor of
100nF. It has a high SVR based on the preregulator.
The 5-V reference supplies 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. In that case the power
dissipation at higher supply voltages has be taken into consideration.
The output signals of the undervoltage detector and the power-on-reset circuitry are logically AND
connected.
OUT1
The maximum drain current of the internal switch transistor (N-ch. MOSFET) is 200mA. The maximum
drain voltage is 450V. Negative drain voltages are not allowed.
OUT2
The maximum source current of the internal transistor is 200mA. The maximum source voltage is 1V.
Negative source voltages are not allowed.
MODA and 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
IN
The high-impedance 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. It is recommended to limit the maximum input voltage to the value of the
VDDC. The input IN is protected against negative voltages up to -80V. The input impedance can be
lowered with 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.
According to the four input modes (programmed at MODA, MODB) are the following variants for the input
control possible:
June 1999 alpha mi croelectronics gm bh Page 5/12
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 can be (1 ... 2) *TPOSC.
The functions current-mode control, voltage-mode control, overexcitation, 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 input 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 ì1620 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]
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.
Page 6/12 alpha mi croelectronics gm bh June 1999
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 internal switching transistor at the rising oscillator voltage and
the turn-off of the transistor at the falling oscillator voltage.
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.
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 or mode 2 overexcitation is automatically performed, also in the present of an input
signal during temperature shutdown.
In case of mode 3 or mode 4 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.
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)
June 1999 alpha mi croelectronics gm bh Page 7/12
INST
These input is intended for the use of relays with a separate final-position contact.
The ì1620 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.
OST
If there is an error event (undervoltage, overtemperature, final position contact, etc.), the status output
shows low level, otherwise it has high level (VREF).
Page 8/12 alpha mi croelectronics gm bh June 1999
Absolute Maximum Ratings
at Tamb = -25°C ... +85°C
Symbol Parameter Min Max Unit
VDD Supply Voltage 0 450 V
IOVP Output Current OVP, t < 10µs 0 40 mA
IOUTp Output Current OUT, t < 200µs 0 1000 mA
IOUT Output Current OUT 0 200 mA
-IVDDC Output Current VDDC 0 20 mA
IIN Input Current IN 0 20 mA
VIN Input Voltage IN -12 VDDC V
IREF Input Current REF -100 0 µA
VMODx Input Voltage MODA, MODB 0 5 V
VCOSC Input Voltage OSC 0 5 V
VCTO Input Voltage CTO 0 5 V
VSEN Input Voltage SEN 0 5 V
VOST Output Voltage OST 0 5 V
IOST Output Current OST 0 2 mA
VINxx Input Voltage INPT, INCO, INCH, INST, IRCR 0 5 V
CVDDC Capacity of CVDDC 1µF
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 18 400 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 -25 +85 °C
DC Characteristics
at Ta = -25°C ... 85°C, VDD = 400V, RREF = 30kW; unless otherwise specified
Symbol Parameter Conditions Min Typ Max Unit
IDD Current Consumption OUT = open,
IN = turn ON 23mA
VOUT Output current Ta = 25°C, IOUT = 200mA 5 VV
VDD LON
VDD LOF
Undervoltage Lockout Turn on
Turn off 15
13 V
V
VREF LON
VREF LOF
Power on Reset Turn on
Turn off 4.0
4.0 V
V
/ VREF / Reference Voltage -IREF = 100µA 4.75 5.0 5.25 V
aSEN Gain OVSEN Ta= 25°C
VSENSE = 100 mV 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 = 400V, 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 ú1624 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)
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
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
10
9
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
1624DSHc.doc
