PCA2117DUGSSLASHDA datasheet(42/107 Pages) NXP

42 / 107 page

PCA2117

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Product data sheet

Rev. 4 — 8 April 2015

42 of 107

NXP Semiconductors

PCA2117

Automotive LCD driver for character displays

The digital temperature filter introduces a certain delay in the measurement of the

temperature. This behavior is illustrated in Figure 24.

8.4.5.2

Temperature adjustment of the VLCD

Due to the temperature dependency of the liquid crystal viscosity, the LCD supply voltage

may have to be adjusted at different temperatures to maintain optimal contrast. The

temperature characteristics of the liquid are provided by the LCD manufacturer. The slope

has to be set to compensate for the liquid behavior. Internal temperature compensation

can be enabled via bit TCE (see Table 32 on page 26).

The ambient temperature range is split up into 4 regions (see Figure 25) and to each a

different temperature coefficient can be applied.

Fig 23. Temperature measurement block with digital temperature filter

(1) Environment temperature, T1 (

C).

(2) Measured temperature, T2 (

C).

(3) Measurement temperature variation,

T

meas =T2  T1.

Fig 24. Temperature measurement delay

PCA2117DUGS/DA Datasheet(PDF) 42 Page - NXP Semiconductors