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PDF TTP932 Data sheet ( Hoja de datos )
| Número de pieza | TTP932 | |
| Descripción | 1A LED Driver | |
| Fabricantes | TONTEK | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de TTP932 (archivo pdf) en la parte inferior de esta página. Total 21 Páginas | ||
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TTP932
1A LED Driver with internal switch
Outline
TTP932 is a high efficiency , constant current , continuous mode inductive step-down
converter, designed for driving constant current to high power（single or multiple）LED with
only 4 external components. TTP932 operates from input supply between 5V and 33V and
provides an externally adjustable output current of up to 1A.
The TTP932 is specifically designed with PFM control to enhance the efficiency up to 95% .
The Output current can be modify by an external resister , and can adjusted , by applying an
external control signal to the DIM pin , The DIM pin will accept a PWM waveform.
Additionally , to ensure the system reliability , TTP932 is built-in with over temperature
protection, and LED open-circuit short-circuit protection to protect system from being
damaged.
Characteristic
1A output current
Wide input voltage range：5V ～ 33V
High efficiency（up to 95%）
Internal NDMOS power switch
Single pin on／off and brightness control using PWM
Hysteretic PFM improves efficiency at light loads
With Thermal、Soft start、LED open-short detect protection
Only 4 External Components
Up to 1Mhz switching frequency
Typical 3% output current accuracy
Applications
High power LED lighting
Automotive LED lighting
Low voltage industrial lighting
LED back-up lighting
Constant Current Source
2015/11/30
Page 1 of 21
Version：3.3
1 page  
Block diagram
TTP932
Device description
The device, in conjunction with the coil（L1）and current sense resistor（RS）, forms a selfoscillating
continuous-mode buck converter.
Ⅰ. Device operation（Refer to block diagram and Figure 1 - Operating waveforms）
Operation can be best understood by assuming that the DIM pin of the device is unconnected
and the voltage on this pin（VDIM）appears directly at the（+）input of the comparator.
When input voltage VIN is first applied, the initial current in L1 and RS is zero and there is no
output from the current sense circuit. Under this condition, the（-）input to the comparator is at
ground and its output is high. This turns MN on and switches the SW pin low, causing current to
flow from VIN to ground, via RS, L1 and the LED（s）. The current rises at a rate determined by
VIN and L1 to produce a voltage ramp（VSENSE）across RS. The supply referred voltage
VSENSE is forced across internal resistor R1 by the current sense circuit and produces a
proportional current in internal resistors R2 and R3. This produces a ground referred rising
voltage at the（-）input of the comparator. When this reaches the threshold voltage（Vref）, the
comparator output switches low and MN turns off. The comparator output also drives another
NMOS switch, which bypasses internal resistor R3 to provide a controlled amount of hysteresis.
The hysteresis is set by R3 to be nominally 15% of VADJ.
When MN is off, the current in L1 continues to flow via D1 and the LED（s）back to VIN. The
current decays at a rate determined by the LED（s）and diode forward voltages to produce a
falling voltage at the input of the comparator. When this voltage returns to VADJ, the comparator
output switches high again. This cycle of events repeats, with the comparator input ramping
between limits of Vref ± 15%.
2015/11/30
Page 5 of 21
Version：3.3
5 Page 
TTP932
Output current vs. input voltage @2-LED in cascaded, IOUT=370mA
Output current vs. input voltage @3-LED in cascaded, IOUT=370mA
5. Output Current vs. LED Cascaded Number at Various Input Voltage
Output current vs. LED cascaded number @L=22uH、IOUT=370mA
2015/11/30
Page 11 of 21
Version：3.3
11 Page | ||
| Páginas | Total 21 Páginas | |
| PDF Descargar | [ Datasheet TTP932.PDF ] | |
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