TLD5085EJ_1 Datasheet, PDF (9/16 Pages) Infineon Technologies AG – 1.8A DC/DC Step-Down Converter

TLD5085EJ
Enable, Thermal Shutdown and PWM Dimming Function
6
Enable, Thermal Shutdown and PWM Dimming Function
6.1
Description
Enable Function: With the enable pin (EN) the device can be set in off-state reducing the current consumption to
typ. 0.1µA. The enable function features an integrated pull down resistor which ensures that the IC is shut down
and the power-switch is off in case the pin EN is not connected.
Device Wake Up Behavior: The device initialization is triggered either by the EN voltage level crossing the turn-
on threshold, rising supply voltage (during EN=H), and also when the device restarts after a thermal shutdown.
The softstart ramp starts after the BDS external capacitor is charged.
Overtemperature Behavior: The integrated thermal shutdown function turns the power-switch off in case of
overtemperature. The typ. junction shutdown temperature is 175°C, with a min. of 150°C. After cooling down the
IC will automatically restart operation. The thermal shutdown is an integrated protection function designed to
prevent IC destruction when operating under fault conditions. It must not be used for normal operation.
PWM Dimming Function: The PWMI signal directly controls the gate driver of the integrated power-switch by
overriding the internal control signals.
6.2
Electrical Characteristics Enable, Bias, Thermal Shutdown and PWM Dimming
Electrical Characteristics: Enable, Bias and Thermal Shutdown
V_S = 6.0 V to 40 V, T_j = -40 °C to +150 °C, all voltages with respect to ground (unless otherwise specified)
Pos. Parameter
Symbol
Limit Values
Unit Conditions
Min. Typ. Max.
6.2.1 Current Consumption,
shut down mode
I_q,OFF
–
0.1
2
µA
V_EN = 0.8V;
T_j < 105°C; V_S = 16V
1)
6.2.2 Current Consumption,
I_q,ON
–
–
7
mA V_EN = 5.0V; I_CC = 0mA;
active mode
V_S = 16V
6.2.3 Current Consumption,
I_q,ON
–
–
10
mA V_EN = 5.0V; I_CC = 1.8A;
active mode
V_S = 16V
1)
6.2.4 Enable high signal valid
V_EN,hi
3
–
–
V
–
6.2.5
6.2.6
Enable low signal valid
Enable hysteresis
V_EN,lo
–
V_EN,HY
50
–
0.8
V
–
200
400
mV
1)
6.2.7 Enable high input current I_EN,hi
–
–
30
µA
V_EN = 16V
6.2.8 Enable low input current I_EN,lo
–
0.1
1
µA
V_EN = 0.5V
6.2.9 PWMI high threshold
V_PWMI,hi 3
–
–
V
–
6.2.10 PWMI low threshold
V_PWMI,lo –
–
0.8
V
–
6.2.11 PWMI turn-on delay
t_PWM,ON –
–
5
µs
2)
6.2.12 PWMI turn-off delay
t_PWM,OFF –
–
5
µs
–
6.2.13 Over temperature shutdown T_j,sd
150 175 190 °C
1)
6.2.14 Over temperature shutdown T_{j,sd_hyst} –
15
–
K
1)
hysteresis
1) Specified by design. Not subject to production test.
2) At startup current flowing in C_BU1, recommended max. PWM frequency 1kHz@370kHz f_sw
Datasheet
9
Rev. 1.1, 2009-12-16