EPC635 datasheet(36/97 Pages) EPC

36 / 97 page

ADC Resolution

Name

Address

8-bit

9-bit

10-bit

11-bit

12-bit

ADC_ramp

0xCD

0x5B

0x9B

0xDB

0x13

n/a

ISOURCE_CLK_divider

0x88

0x2E

0x34

0x3A

0x3F

n/a

SIR_lo

0x9D

0x3B

0x42

0x49

0x50

n/a

Table 15: ADC resolution setting for unsigned data format (adc_skip_signmsb_en = 1)

5.7.3. Pixel saturation detection

The pixels collect continuously modulated and non-modulated ambient light during the integration period. Depending on these light intens-

ities, sometimes the pixels collect more charge (over-exposure) than they can accommodate in their storage gates (refer to Figure 30). In

such a case, the 12 bit sample data is not valid and cannot be used. Therefore, each pixel generates a “saturation detection” flag along

with the sample data, so that the data can be discarded by the application.

The saturation flag is generated in the pixel binning modes as well. It is set when one or more storage gates of the binned pixels is/are sat-

urated or the sum thereof. Due to this architecture, two binned pixels cannot collect twice the full storage gate charge.

The saturation detection flag is transmitted via XSYNC_SAT_CFG pin synchronously to the DATA[11:0] for every 12 bit pixel sample. If

XSYNC_SAT_CFG pin is programmed for an another function by setting tcmi_xsync_sat_sel = 0 or not connected at all,

tcmi_data_sat_en = 1 can optionally drive all DATA[11:0] pins to 0xFFF when the pixel is saturated (see TCMI_polarity register in chapter

8.4., Table 41, TCMI registers). In this configuration, the application must discard those samples equal to 0xFFF, otherwise use it for calcu-

lation.

5.7.4. Ambient-light suppression

An important function of the 3D TOF pixel is the ambient-light suppression. It is the ability to separate the reflected modulated light and

suppress the the ambient light. The user has not to take care of this because it is built-in in the pixel. It removes the common mode distor -

tion (DC or low frequent signal) caused by foreign light sources (e.g. sunlight, daylight, room illumination, etc) automatically from the mea -

surement signal by using only the charge difference in the storage gates (see Figure 30).

Similar to the system sensitivity to modulated light, is the ambient-light suppression also a function of the integration time. The longer the

integration time, the more unwanted light will be detected.

Table 7 lists the minimum values for the ambient-light suppression as a function of the wavelength and as well as compared to sunlight.

Notes:

■ The ambient-light suppression of the chip must not be mistaken with the ambient-light measurement. It is a fixed built-in functionality

which is removing the ambient-light from the measurement signal only.

■ DC and AC photo-signals can be generated by ambient-light (e.g. sunlight) or by cross-talk from the IR-LEDs. However, if these are

above the stated maximum values, the sensor or the input electronics are saturated. This blocks the detection of the TOF modulation

signal.

5.8. Temperature sensor

A temperature sensor is located near the pixel-field (Figure 29). It is not calibrated and reads the values as they are. Values can be read

on-the-fly via I2C interface while frame acquisition is going on. The sensor is sampled synchronously to the row readout cycles. Four con-

secutive readings are summed up to the resulting 14 bit value written into the Sum_Temp_xx_hi/lo registers (see Table 40, Temperature

sensor registers). After frame start, four row readout cycles must be performed for getting a valid value because every frame-start resets

the temperature sensor.

An approximative temperature can be calculated from the values Sum_Temp_ti to (chapter 8.6.6), Temp_ti_cal1, Temp_ti_cal2 (refer to

chapter 8.7.24 for description and validity) according the following formula

Temperture T [ºC]

= (

Sum_Temp_ti

− 2'048LSB

)−1'400LSB+(Temp_ti_cal1−127LSB)

4.68 LSB/ºC

+ (Temp_ti_cal2 − 127LSB)⋅0.01 LSB/ºC

+ 27ºC

Characteristics subject to change without notice

36 / 97

Datasheet_epc635-V1.02

EPC635 数据表(PDF) 36 Page - Espros Photonics corp

EPC635 数据表(HTML) 36 Page - Espros Photonics corp

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97

数据表下载